/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.commons.pool2.impl;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertInstanceOf;
  import static org.junit.jupiter.api.Assertions.assertNotEquals;
  import static org.junit.jupiter.api.Assertions.assertNotNull;
  import static org.junit.jupiter.api.Assertions.assertNull;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  import static org.junit.jupiter.api.Assertions.fail;
  
  import java.lang.management.ManagementFactory;
  import java.lang.ref.WeakReference;
  import java.nio.charset.UnsupportedCharsetException;
  import java.time.Duration;
  import java.time.Instant;
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.List;
  import java.util.NoSuchElementException;
  import java.util.Objects;
  import java.util.Random;
  import java.util.Set;
  import java.util.Timer;
  import java.util.TimerTask;
  import java.util.concurrent.Semaphore;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicBoolean;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import javax.management.MBeanServer;
  import javax.management.ObjectName;
  
  import org.apache.commons.lang3.ThreadUtils;
  import org.apache.commons.lang3.time.DurationUtils;
  import org.apache.commons.pool2.BasePooledObjectFactory;
  import org.apache.commons.pool2.ObjectPool;
  import org.apache.commons.pool2.PoolUtils;
  import org.apache.commons.pool2.PooledObject;
  import org.apache.commons.pool2.PooledObjectFactory;
  import org.apache.commons.pool2.SwallowedExceptionListener;
  import org.apache.commons.pool2.TestBaseObjectPool;
  import org.apache.commons.pool2.VisitTracker;
  import org.apache.commons.pool2.VisitTrackerFactory;
  import org.apache.commons.pool2.Waiter;
  import org.apache.commons.pool2.WaiterFactory;
  import org.junit.jupiter.api.AfterEach;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Disabled;
  import org.junit.jupiter.api.Test;
  import org.junit.jupiter.api.Timeout;
  
  /**
   */
  public class TestGenericObjectPool extends TestBaseObjectPool {
  
      private final class ConcurrentBorrowAndEvictThread extends Thread {
          private final boolean borrow;
          public String obj;
  
          public ConcurrentBorrowAndEvictThread(final boolean borrow) {
              this.borrow = borrow;
          }
  
          @Override
          public void run() {
              try {
                  if (borrow) {
                      obj = genericObjectPool.borrowObject();
                  } else {
                      genericObjectPool.evict();
                  }
              } catch (final Exception e) {
                  // Ignore.
              }
          }
      }
  
      private static final class CreateErrorFactory extends BasePooledObjectFactory<String> {
  
          private final Semaphore semaphore = new Semaphore(0);
 
         @Override
         public String create() throws InterruptedException {
             semaphore.acquire();
             throw new UnknownError("wiggle");
         }
 
         public boolean hasQueuedThreads() {
             return semaphore.hasQueuedThreads();
         }
 
         public void release() {
             semaphore.release();
         }
 
         @Override
         public PooledObject<String> wrap(final String obj) {
             return new DefaultPooledObject<>(obj);
         }
     }
 
     private static final class CreateFailFactory extends BasePooledObjectFactory<String> {
 
         private final Semaphore semaphore = new Semaphore(0);
 
         @Override
         public String create() throws InterruptedException {
             semaphore.acquire();
             throw new UnsupportedCharsetException("wibble");
         }
 
         public boolean hasQueuedThreads() {
             return semaphore.hasQueuedThreads();
         }
 
         public void release() {
             semaphore.release();
         }
 
         @Override
         public PooledObject<String> wrap(final String obj) {
             return new DefaultPooledObject<>(obj);
         }
     }
 
     private static final class DummyFactory
             extends BasePooledObjectFactory<Object> {
         @Override
         public Object create() {
             return null;
         }
         @Override
         public PooledObject<Object> wrap(final Object value) {
             return new DefaultPooledObject<>(value);
         }
     }
 
     private static final class EvictionThread<T> extends Thread {
 
         private final GenericObjectPool<T> pool;
 
         public EvictionThread(final GenericObjectPool<T> pool) {
             this.pool = pool;
         }
 
         @Override
         public void run() {
             try {
                 pool.evict();
             } catch (final Exception e) {
                 // Ignore
             }
         }
     }
 
     /**
      * Factory that creates HashSets.  Note that this means
      *  0) All instances are initially equal (not discernible by equals)
      *  1) Instances are mutable and mutation can cause change in identity / hash code.
      */
     private static final class HashSetFactory
             extends BasePooledObjectFactory<HashSet<String>> {
         @Override
         public HashSet<String> create() {
             return new HashSet<>();
         }
         @Override
         public PooledObject<HashSet<String>> wrap(final HashSet<String> value) {
             return new DefaultPooledObject<>(value);
         }
     }
 
     /**
      * Attempts to invalidate an object, swallowing IllegalStateException.
      */
     static class InvalidateThread implements Runnable {
         private final String obj;
         private final ObjectPool<String> pool;
         private boolean done;
         public InvalidateThread(final ObjectPool<String> pool, final String obj) {
             this.obj = obj;
             this.pool = pool;
         }
         public boolean complete() {
             return done;
         }
         @Override
         public void run() {
             try {
                 pool.invalidateObject(obj);
             } catch (final IllegalStateException ex) {
                 // Ignore
             } catch (final Exception ex) {
                 fail("Unexpected exception " + ex.toString());
             } finally {
                 done = true;
             }
         }
     }
 
     private static final class InvalidFactory
             extends BasePooledObjectFactory<Object> {
 
         @Override
         public Object create() {
             return new Object();
         }
         @Override
         public boolean validateObject(final PooledObject<Object> obj) {
             Waiter.sleepQuietly(1000);
             return false;
         }
 
         @Override
         public PooledObject<Object> wrap(final Object value) {
             return new DefaultPooledObject<>(value);
         }
     }
 
     public static class SimpleFactory implements PooledObjectFactory<String> {
         int makeCounter;
 
         int activationCounter;
 
         int validateCounter;
 
         int activeCount;
 
         boolean evenValid = true;
 
         boolean oddValid = true;
 
         boolean exceptionOnPassivate;
 
         boolean exceptionOnActivate;
 
         boolean exceptionOnDestroy;
 
         boolean exceptionOnValidate;
 
         boolean enableValidation = true;
 
         long destroyLatency;
 
         long makeLatency;
 
         long validateLatency;
 
         int maxTotal = Integer.MAX_VALUE;
 
         public SimpleFactory() {
             this(true);
         }
 
         public SimpleFactory(final boolean valid) {
             this(valid, valid);
         }
 
         public SimpleFactory(final boolean evalid, final boolean ovalid) {
             evenValid = evalid;
             oddValid = ovalid;
         }
 
         @Override
         public void activateObject(final PooledObject<String> obj) throws Exception {
             final boolean hurl;
             final boolean evenTest;
             final boolean oddTest;
             final int counter;
             synchronized (this) {
                 hurl = exceptionOnActivate;
                 evenTest = evenValid;
                 oddTest = oddValid;
                 counter = activationCounter++;
             }
             if (hurl && !(counter % 2 == 0 ? evenTest : oddTest)) {
                 throw new Exception();
             }
         }
 
         @Override
         public void destroyObject(final PooledObject<String> obj) throws Exception {
             final long waitLatency;
             final boolean hurl;
             synchronized (this) {
                 waitLatency = destroyLatency;
                 hurl = exceptionOnDestroy;
             }
             if (waitLatency > 0) {
                 doWait(waitLatency);
             }
             synchronized (this) {
                 activeCount--;
             }
             if (hurl) {
                 throw new Exception();
             }
         }
 
         private void doWait(final long latency) {
             Waiter.sleepQuietly(latency);
         }
 
         public synchronized int getMakeCounter() {
             return makeCounter;
         }
 
         public synchronized boolean isThrowExceptionOnActivate() {
             return exceptionOnActivate;
         }
 
         public synchronized boolean isValidationEnabled() {
             return enableValidation;
         }
 
         @Override
         public PooledObject<String> makeObject() {
             final long waitLatency;
             synchronized (this) {
                 activeCount++;
                 if (activeCount > maxTotal) {
                     throw new IllegalStateException(
                         "Too many active instances: " + activeCount);
                 }
                 waitLatency = makeLatency;
             }
             if (waitLatency > 0) {
                 doWait(waitLatency);
             }
             final int counter;
             synchronized (this) {
                 counter = makeCounter++;
             }
             return new DefaultPooledObject<>(String.valueOf(counter));
         }
 
         @Override
         public void passivateObject(final PooledObject<String> obj) throws Exception {
             final boolean hurl;
             synchronized (this) {
                 hurl = exceptionOnPassivate;
             }
             if (hurl) {
                 throw new Exception();
             }
         }
 
         public synchronized void setDestroyLatency(final long destroyLatency) {
             this.destroyLatency = destroyLatency;
         }
 
         public synchronized void setEvenValid(final boolean valid) {
             evenValid = valid;
         }
 
         public synchronized void setMakeLatency(final long makeLatency) {
             this.makeLatency = makeLatency;
         }
 
         public synchronized void setMaxTotal(final int maxTotal) {
             this.maxTotal = maxTotal;
         }
 
         public synchronized void setOddValid(final boolean valid) {
             oddValid = valid;
         }
 
         public synchronized void setThrowExceptionOnActivate(final boolean b) {
             exceptionOnActivate = b;
         }
 
         public synchronized void setThrowExceptionOnDestroy(final boolean b) {
             exceptionOnDestroy = b;
         }
 
         public synchronized void setThrowExceptionOnPassivate(final boolean bool) {
             exceptionOnPassivate = bool;
         }
 
         public synchronized void setThrowExceptionOnValidate(final boolean bool) {
             exceptionOnValidate = bool;
         }
 
         public synchronized void setValid(final boolean valid) {
             setEvenValid(valid);
             setOddValid(valid);
         }
 
         public synchronized void setValidateLatency(final long validateLatency) {
             this.validateLatency = validateLatency;
         }
 
         public synchronized void setValidationEnabled(final boolean b) {
             enableValidation = b;
         }
 
         @Override
         public boolean validateObject(final PooledObject<String> obj) {
             final boolean validate;
             final boolean throwException;
             final boolean evenTest;
             final boolean oddTest;
             final long waitLatency;
             final int counter;
             synchronized (this) {
                 validate = enableValidation;
                 throwException = exceptionOnValidate;
                 evenTest = evenValid;
                 oddTest = oddValid;
                 counter = validateCounter++;
                 waitLatency = validateLatency;
             }
             if (waitLatency > 0) {
                 doWait(waitLatency);
             }
             if (throwException) {
                 throw new RuntimeException("validation failed");
             }
             if (validate) {
                 return counter%2 == 0 ? evenTest : oddTest;
             }
             return true;
         }
     }
 
     public static class TestEvictionPolicy<T> implements EvictionPolicy<T> {
 
         private final AtomicInteger callCount = new AtomicInteger();
 
         @Override
         public boolean evict(final EvictionConfig config, final PooledObject<T> underTest,
                 final int idleCount) {
             return callCount.incrementAndGet() > 1500;
         }
     }
 
     static class TestThread<T> implements Runnable {
 
         /** Source of random delay times */
         private final Random random;
 
         /** Pool to borrow from */
         private final ObjectPool<T> pool;
 
         /** Number of borrow attempts */
         private final int iter;
 
         /** Delay before each borrow attempt */
         private final int startDelay;
 
         /** Time to hold each borrowed object before returning it */
         private final int holdTime;
 
         /** Whether or not start and hold time are randomly generated */
         private final boolean randomDelay;
 
         /** Object expected to be borrowed (fail otherwise) */
         private final Object expectedObject;
 
         private volatile boolean complete;
         private volatile boolean failed;
         private volatile Throwable error;
 
         public TestThread(final ObjectPool<T> pool) {
             this(pool, 100, 50, true, null);
         }
 
         public TestThread(final ObjectPool<T> pool, final int iter) {
             this(pool, iter, 50, true, null);
         }
 
         public TestThread(final ObjectPool<T> pool, final int iter, final int delay) {
             this(pool, iter, delay, true, null);
         }
 
         public TestThread(final ObjectPool<T> pool, final int iter, final int delay,
                 final boolean randomDelay) {
             this(pool, iter, delay, randomDelay, null);
         }
 
         public TestThread(final ObjectPool<T> pool, final int iter, final int delay,
                 final boolean randomDelay, final Object obj) {
             this(pool, iter, delay, delay, randomDelay, obj);
         }
 
         public TestThread(final ObjectPool<T> pool, final int iter, final int startDelay,
             final int holdTime, final boolean randomDelay, final Object obj) {
        this.pool = pool;
        this.iter = iter;
        this.startDelay = startDelay;
        this.holdTime = holdTime;
        this.randomDelay = randomDelay;
        this.random = this.randomDelay ? new Random() : null;
        this.expectedObject = obj;
     }
 
         public boolean complete() {
             return complete;
         }
 
         public boolean failed() {
             return failed;
         }
 
         @Override
         public void run() {
             for (int i = 0; i < iter; i++) {
                 final long actualStartDelay = randomDelay ? (long) random.nextInt(startDelay) : startDelay;
                 final long actualHoldTime = randomDelay ? (long) random.nextInt(holdTime) : holdTime;
                 Waiter.sleepQuietly(actualStartDelay);
                 T obj = null;
                 try {
                     obj = pool.borrowObject();
                 } catch (final Exception e) {
                     error = e;
                     failed = true;
                     complete = true;
                     break;
                 }
 
                 if (expectedObject != null && !expectedObject.equals(obj)) {
                     error = new Throwable("Expected: " + expectedObject + " found: " + obj);
                     failed = true;
                     complete = true;
                     break;
                 }
 
                 Waiter.sleepQuietly(actualHoldTime);
                 try {
                     pool.returnObject(obj);
                 } catch (final Exception e) {
                     error = e;
                     failed = true;
                     complete = true;
                     break;
                 }
             }
             complete = true;
         }
     }
 
     /*
      * Very simple test thread that just tries to borrow an object from
      * the provided pool returns it after a wait
      */
     static class WaitingTestThread extends Thread {
         private final GenericObjectPool<String> pool;
         private final long pause;
         private Throwable thrown;
 
         private long preBorrowMillis; // just before borrow
         private long postBorrowMillis; //  borrow returned
         private long postReturnMillis; // after object was returned
         private long endedMillis;
         private String objectId;
 
         public WaitingTestThread(final GenericObjectPool<String> pool, final long pause) {
             this.pool = pool;
             this.pause = pause;
             this.thrown = null;
         }
 
         @Override
         public void run() {
             try {
                 preBorrowMillis = System.currentTimeMillis();
                 final String obj = pool.borrowObject();
                 objectId = obj;
                 postBorrowMillis = System.currentTimeMillis();
                 Thread.sleep(pause);
                 pool.returnObject(obj);
                 postReturnMillis = System.currentTimeMillis();
             } catch (final Throwable e) {
                 thrown = e;
             } finally{
                 endedMillis = System.currentTimeMillis();
             }
         }
     }
 
     private static final boolean DISPLAY_THREAD_DETAILS=
     Boolean.getBoolean("TestGenericObjectPool.display.thread.details");
     // To pass this to a Maven test, use:
     // mvn test -DargLine="-DTestGenericObjectPool.display.thread.details=true"
     // @see https://issues.apache.org/jira/browse/SUREFIRE-121
 
     protected GenericObjectPool<String> genericObjectPool;
 
     private SimpleFactory simpleFactory;
 
     @SuppressWarnings("deprecation")
     private void assertConfiguration(final GenericObjectPoolConfig<?> expected, final GenericObjectPool<?> actual) {
         assertEquals(Boolean.valueOf(expected.getTestOnCreate()), Boolean.valueOf(actual.getTestOnCreate()),
                 "testOnCreate");
         assertEquals(Boolean.valueOf(expected.getTestOnBorrow()), Boolean.valueOf(actual.getTestOnBorrow()),
                 "testOnBorrow");
         assertEquals(Boolean.valueOf(expected.getTestOnReturn()), Boolean.valueOf(actual.getTestOnReturn()),
                 "testOnReturn");
         assertEquals(Boolean.valueOf(expected.getTestWhileIdle()), Boolean.valueOf(actual.getTestWhileIdle()),
                 "testWhileIdle");
         assertEquals(Boolean.valueOf(expected.getBlockWhenExhausted()), Boolean.valueOf(actual.getBlockWhenExhausted()),
                 "whenExhaustedAction");
         assertEquals(expected.getMaxTotal(), actual.getMaxTotal(), "maxTotal");
         assertEquals(expected.getMaxIdle(), actual.getMaxIdle(), "maxIdle");
         assertEquals(expected.getMaxWaitMillis(), actual.getMaxWaitMillis(), "maxWaitDuration");
         assertEquals(expected.getMaxWaitDuration(), actual.getMaxWaitDuration(), "maxWaitDuration");
         assertEquals(expected.getMinEvictableIdleTimeMillis(), actual.getMinEvictableIdleTimeMillis(),
                 "minEvictableIdleTimeMillis");
         assertEquals(expected.getMinEvictableIdleTime(), actual.getMinEvictableIdleTime(),
                 "minEvictableIdleTime");
         assertEquals(expected.getMinEvictableIdleDuration(), actual.getMinEvictableIdleDuration(),
                 "minEvictableIdleDuration");
         assertEquals(expected.getNumTestsPerEvictionRun(), actual.getNumTestsPerEvictionRun(),
                 "numTestsPerEvictionRun");
         assertEquals(expected.getEvictorShutdownTimeoutDuration(), actual.getEvictorShutdownTimeoutDuration(),
                 "evictorShutdownTimeoutDuration");
         assertEquals(expected.getEvictorShutdownTimeoutMillis(), actual.getEvictorShutdownTimeoutMillis(),
                 "evictorShutdownTimeoutMillis");
         assertEquals(expected.getEvictorShutdownTimeout(), actual.getEvictorShutdownTimeout(),
                 "evictorShutdownTimeout");
         assertEquals(expected.getTimeBetweenEvictionRunsMillis(), actual.getTimeBetweenEvictionRunsMillis(),
                 "timeBetweenEvictionRunsMillis");
         assertEquals(expected.getDurationBetweenEvictionRuns(), actual.getTimeBetweenEvictionRuns(),
                 "timeBetweenEvictionRuns");
         assertEquals(expected.getTimeBetweenEvictionRuns(), actual.getTimeBetweenEvictionRuns(),
                 "timeBetweenEvictionRuns");
     }
 
     private void checkEvict(final boolean lifo) throws Exception {
         // yea this is hairy but it tests all the code paths in GOP.evict()
         genericObjectPool.setSoftMinEvictableIdleDuration(Duration.ofMillis(10));
         genericObjectPool.setSoftMinEvictableIdle(Duration.ofMillis(10));
         genericObjectPool.setSoftMinEvictableIdleTime(Duration.ofMillis(10));
         genericObjectPool.setMinIdle(2);
         genericObjectPool.setTestWhileIdle(true);
         genericObjectPool.setLifo(lifo);
         genericObjectPool.addObjects(5);
         genericObjectPool.evict();
         simpleFactory.setEvenValid(false);
         simpleFactory.setOddValid(false);
         simpleFactory.setThrowExceptionOnActivate(true);
         genericObjectPool.evict();
         genericObjectPool.addObjects(5);
         simpleFactory.setThrowExceptionOnActivate(false);
         simpleFactory.setThrowExceptionOnPassivate(true);
         genericObjectPool.evict();
         simpleFactory.setThrowExceptionOnPassivate(false);
         simpleFactory.setEvenValid(true);
         simpleFactory.setOddValid(true);
         Thread.sleep(125);
         genericObjectPool.evict();
         assertEquals(2, genericObjectPool.getNumIdle());
     }
 
     private void checkEvictionOrder(final boolean lifo) throws Exception {
         checkEvictionOrderPart1(lifo);
         tearDown();
         setUp();
         checkEvictionOrderPart2(lifo);
     }
 
     private void checkEvictionOrderPart1(final boolean lifo) throws Exception {
         genericObjectPool.setNumTestsPerEvictionRun(2);
         genericObjectPool.setMinEvictableIdleTime(Duration.ofMillis(100));
         genericObjectPool.setLifo(lifo);
         for (int i = 0; i < 5; i++) {
             genericObjectPool.addObject();
             Thread.sleep(100);
         }
         // Order, oldest to youngest, is "0", "1", ...,"4"
         genericObjectPool.evict(); // Should evict "0" and "1"
         final Object obj = genericObjectPool.borrowObject();
         assertNotEquals("0", obj, "oldest not evicted");
         assertNotEquals("1", obj, "second oldest not evicted");
         // 2 should be next out for FIFO, 4 for LIFO
         assertEquals(lifo ? "4" : "2", obj, "Wrong instance returned");
     }
 
     private void checkEvictionOrderPart2(final boolean lifo) throws Exception {
         // Two eviction runs in sequence
         genericObjectPool.setNumTestsPerEvictionRun(2);
         genericObjectPool.setMinEvictableIdleTime(Duration.ofMillis(100));
         genericObjectPool.setLifo(lifo);
         for (int i = 0; i < 5; i++) {
             genericObjectPool.addObject();
             Thread.sleep(100);
         }
         genericObjectPool.evict(); // Should evict "0" and "1"
         genericObjectPool.evict(); // Should evict "2" and "3"
         final Object obj = genericObjectPool.borrowObject();
         assertEquals("4", obj, "Wrong instance remaining in pool");
     }
 
     private void checkEvictorVisiting(final boolean lifo) throws Exception {
         VisitTracker<Object> obj;
         VisitTrackerFactory<Object> trackerFactory = new VisitTrackerFactory<>();
         try (GenericObjectPool<VisitTracker<Object>> trackerPool = new GenericObjectPool<>(trackerFactory)) {
             trackerPool.setNumTestsPerEvictionRun(2);
             trackerPool.setMinEvictableIdleTime(Duration.ofMillis(-1));
             trackerPool.setTestWhileIdle(true);
             trackerPool.setLifo(lifo);
             trackerPool.setTestOnReturn(false);
             trackerPool.setTestOnBorrow(false);
             for (int i = 0; i < 8; i++) {
                 trackerPool.addObject();
             }
             trackerPool.evict(); // Visit oldest 2 - 0 and 1
             obj = trackerPool.borrowObject();
             trackerPool.returnObject(obj);
             obj = trackerPool.borrowObject();
             trackerPool.returnObject(obj);
             // borrow, return, borrow, return
             // FIFO will move 0 and 1 to end
             // LIFO, 7 out, then in, then out, then in
             trackerPool.evict(); // Should visit 2 and 3 in either case
             for (int i = 0; i < 8; i++) {
                 final VisitTracker<Object> tracker = trackerPool.borrowObject();
                 if (tracker.getId() >= 4) {
                     assertEquals(0, tracker.getValidateCount(), "Unexpected instance visited " + tracker.getId());
                 } else {
                     assertEquals(1, tracker.getValidateCount(), "Instance " + tracker.getId() + " visited wrong number of times.");
                 }
             }
         }
 
         trackerFactory = new VisitTrackerFactory<>();
         try (GenericObjectPool<VisitTracker<Object>> trackerPool = new GenericObjectPool<>(trackerFactory)) {
             trackerPool.setNumTestsPerEvictionRun(3);
             trackerPool.setMinEvictableIdleTime(Duration.ofMillis(-1));
             trackerPool.setTestWhileIdle(true);
             trackerPool.setLifo(lifo);
             trackerPool.setTestOnReturn(false);
             trackerPool.setTestOnBorrow(false);
             for (int i = 0; i < 8; i++) {
                 trackerPool.addObject();
             }
             trackerPool.evict(); // 0, 1, 2
             trackerPool.evict(); // 3, 4, 5
             obj = trackerPool.borrowObject();
             trackerPool.returnObject(obj);
             obj = trackerPool.borrowObject();
             trackerPool.returnObject(obj);
             obj = trackerPool.borrowObject();
             trackerPool.returnObject(obj);
             // borrow, return, borrow, return
             // FIFO 3,4,5,6,7,0,1,2
             // LIFO 7,6,5,4,3,2,1,0
             // In either case, pointer should be at 6
             trackerPool.evict();
             // Should hit 6,7,0 - 0 for second time
             for (int i = 0; i < 8; i++) {
                 final VisitTracker<Object> tracker = trackerPool.borrowObject();
                 if (tracker.getId() != 0) {
                     assertEquals(1, tracker.getValidateCount(),
                             "Instance " + tracker.getId() + " visited wrong number of times.");
                 } else {
                     assertEquals(2, tracker.getValidateCount(),
                             "Instance " + tracker.getId() + " visited wrong number of times.");
                 }
             }
         }
 
         // Randomly generate a pools with random numTests
         // and make sure evictor cycles through elements appropriately
         final int[] smallPrimes = { 2, 3, 5, 7 };
         final Random random = new Random();
         random.setSeed(System.currentTimeMillis());
         for (int i = 0; i < 4; i++) {
             for (int j = 0; j < 5; j++) {
                 try (GenericObjectPool<VisitTracker<Object>> trackerPool = new GenericObjectPool<>(trackerFactory)) {
                     trackerPool.setNumTestsPerEvictionRun(smallPrimes[i]);
                     trackerPool.setMinEvictableIdleTime(Duration.ofMillis(-1));
                     trackerPool.setTestWhileIdle(true);
                     trackerPool.setLifo(lifo);
                     trackerPool.setTestOnReturn(false);
                     trackerPool.setTestOnBorrow(false);
                     trackerPool.setMaxIdle(-1);
                     final int instanceCount = 10 + random.nextInt(20);
                     trackerPool.setMaxTotal(instanceCount);
                     for (int k = 0; k < instanceCount; k++) {
                         trackerPool.addObject();
                     }
 
                     // Execute a random number of evictor runs
                     final int runs = 10 + random.nextInt(50);
                     for (int k = 0; k < runs; k++) {
                         trackerPool.evict();
                     }
 
                     // Number of times evictor should have cycled through the pool
                     final int cycleCount = runs * trackerPool.getNumTestsPerEvictionRun() / instanceCount;
 
                     // Look at elements and make sure they are visited cycleCount
                     // or cycleCount + 1 times
                     VisitTracker<Object> tracker = null;
                     int visitCount = 0;
                     for (int k = 0; k < instanceCount; k++) {
                         tracker = trackerPool.borrowObject();
                         assertTrue(trackerPool.getNumActive() <= trackerPool.getMaxTotal());
                         visitCount = tracker.getValidateCount();
                         assertTrue(visitCount >= cycleCount && visitCount <= cycleCount + 1);
                     }
                 }
             }
         }
     }
 
     private BasePooledObjectFactory<String> createDefaultPooledObjectFactory() {
         return new BasePooledObjectFactory<String>() {
             @Override
             public String create() {
                 // fake
                 return null;
             }
 
             @Override
             public PooledObject<String> wrap(final String obj) {
                 // fake
                 return new DefaultPooledObject<>(obj);
             }
         };
     }
 
     private BasePooledObjectFactory<String> createNullPooledObjectFactory() {
         return new BasePooledObjectFactory<String>() {
             @Override
             public String create() {
                 // fake
                 return null;
             }
 
             @Override
             public PooledObject<String> wrap(final String obj) {
                 // fake
                 return null;
             }
         };
     }
 
     private BasePooledObjectFactory<String> createSlowObjectFactory(final Duration sleepDuration) {
         return new BasePooledObjectFactory<String>() {
             @Override
             public String create() throws InterruptedException {
                 ThreadUtils.sleep(sleepDuration);
                 return "created";
             }
 
             @Override
             public PooledObject<String> wrap(final String obj) {
                 // fake
                 return new DefaultPooledObject<>(obj);
             }
         };
     }
 
     @Override
     protected Object getNthObject(final int n) {
         return String.valueOf(n);
     }
 
     @Override
     protected boolean isFifo() {
         return false;
     }
 
     @Override
     protected boolean isLifo() {
         return true;
     }
 
     @Override
     protected ObjectPool<String> makeEmptyPool(final int minCap) {
         final GenericObjectPool<String> mtPool = new GenericObjectPool<>(new SimpleFactory());
         mtPool.setMaxTotal(minCap);
        mtPool.setMaxIdle(minCap);
        return mtPool;
     }
 
     @Override
     protected <E extends Exception> ObjectPool<Object> makeEmptyPool(final PooledObjectFactory<Object> fac) {
         return new GenericObjectPool<>(fac);
     }
 
     /**
      * Kicks off <numThreads> test threads, each of which will go through
      * <iterations> borrow-return cycles with random delay times <= delay
      * in between.
      */
     private <T> void runTestThreads(final int numThreads, final int iterations, final int delay, final GenericObjectPool<T> testPool) {
         final TestThread<T>[] threads = new TestThread[numThreads];
         for (int i = 0; i < numThreads; i++) {
             threads[i] = new TestThread<>(testPool, iterations, delay);
             final Thread t = new Thread(threads[i]);
             t.start();
         }
         for (int i = 0; i < numThreads; i++) {
             while (!threads[i].complete()) {
                 Waiter.sleepQuietly(500L);
             }
             if (threads[i].failed()) {
                 fail("Thread " + i + " failed: " + threads[i].error.toString());
             }
         }
     }
 
     @BeforeEach
     public void setUp() {
         simpleFactory = new SimpleFactory();
         genericObjectPool = new GenericObjectPool<>(simpleFactory);
     }
 
     @AfterEach
     public void tearDown() throws Exception {
         final ObjectName jmxName = genericObjectPool.getJmxName();
         final String poolName = Objects.toString(jmxName, null);
 
         genericObjectPool.clear();
         genericObjectPool.close();
         genericObjectPool = null;
         simpleFactory = null;
 
         final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
         final Set<ObjectName> result = mbs.queryNames(new ObjectName("org.apache.commoms.pool2:type=GenericObjectPool,*"), null);
         // There should be no registered pools at this point
         final int registeredPoolCount = result.size();
         final StringBuilder msg = new StringBuilder("Current pool is: ");
         msg.append(poolName);
         msg.append("  Still open pools are: ");
         for (final ObjectName name : result) {
             // Clean these up ready for the next test
             msg.append(name.toString());
             msg.append(" created via\n");
             msg.append(mbs.getAttribute(name, "CreationStackTrace"));
             msg.append('\n');
             mbs.unregisterMBean(name);
         }
         assertEquals(0, registeredPoolCount, msg.toString());
 
         // Make sure that EvictionTimer executor is shut down.
         Thread.yield();
         if (EvictionTimer.getExecutor() != null) {
             Thread.sleep(1000);
         }
         assertNull(EvictionTimer.getExecutor(), "EvictionTimer.getExecutor()");
     }
 
     /**
      * Check that a pool that starts an evictor, but is never closed does not leave EvictionTimer executor running. Confirmation check is in
      * {@link #tearDown()}.
      *
      * @throws TestException Custom exception
      * @throws InterruptedException if any thread has interrupted the current thread. The <em>interrupted status</em> of the current thread is cleared when this
      *         exception is thrown.
      */
     @SuppressWarnings("deprecation")
     @Test
     public void testAbandonedPool() throws Exception {
         final GenericObjectPoolConfig<String> config = new GenericObjectPoolConfig<>();
         config.setJmxEnabled(false);
         GenericObjectPool<String> abandoned = new GenericObjectPool<>(simpleFactory, config);
         abandoned.setDurationBetweenEvictionRuns(Duration.ofMillis(100)); // Starts evictor
         assertEquals(abandoned.getRemoveAbandonedTimeout(), abandoned.getRemoveAbandonedTimeoutDuration().getSeconds());
 
         // This is ugly, but forces GC to hit the pool
         final WeakReference<GenericObjectPool<String>> ref = new WeakReference<>(abandoned);
         abandoned = null;
         while (ref.get() != null) {
             System.gc();
             Thread.sleep(100);
         }
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testAddObject() throws Exception {
         assertEquals(0, genericObjectPool.getNumIdle(), "should be zero idle");
         genericObjectPool.addObject();
         assertEquals(1, genericObjectPool.getNumIdle(), "should be one idle");
         assertEquals(0, genericObjectPool.getNumActive(), "should be zero active");
         final String obj = genericObjectPool.borrowObject();
         assertEquals(0, genericObjectPool.getNumIdle(), "should be zero idle");
         assertEquals(1, genericObjectPool.getNumActive(), "should be one active");
         genericObjectPool.returnObject(obj);
         assertEquals(1, genericObjectPool.getNumIdle(), "should be one idle");
         assertEquals(0, genericObjectPool.getNumActive(), "should be zero active");
     }
 
     @Test
     public void testAppendStats() {
         assertFalse(genericObjectPool.getMessageStatistics());
         assertEquals("foo", genericObjectPool.appendStats("foo"));
         try (final GenericObjectPool<?> pool = new GenericObjectPool<>(new SimpleFactory())) {
             pool.setMessagesStatistics(true);
             assertNotEquals("foo", pool.appendStats("foo"));
             pool.setMessagesStatistics(false);
             assertEquals("foo", pool.appendStats("foo"));
         }
     }
 
     /*
      * Note: This test relies on timing for correct execution. There *should* be
      * enough margin for this to work correctly on most (all?) systems but be
      * aware of this if you see a failure of this test.
      */
     @SuppressWarnings({
         "rawtypes", "unchecked"
     })
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testBorrowObjectFairness() throws Exception {
 
         final int numThreads = 40;
         final int maxTotal = 40;
 
         final GenericObjectPoolConfig config = new GenericObjectPoolConfig();
         config.setMaxTotal(maxTotal);
         config.setMaxIdle(maxTotal);
         config.setFairness(true);
         config.setLifo(false);
 
         genericObjectPool = new GenericObjectPool(simpleFactory, config);
 
         // Exhaust the pool
         final String[] objects = new String[maxTotal];
         for (int i = 0; i < maxTotal; i++) {
             objects[i] = genericObjectPool.borrowObject();
         }
 
         // Start and park threads waiting to borrow objects
         final TestThread[] threads = new TestThread[numThreads];
         for(int i=0;i<numThreads;i++) {
             threads[i] = new TestThread(genericObjectPool, 1, 0, 2000, false, String.valueOf(i % maxTotal));
             final Thread t = new Thread(threads[i]);
             t.start();
             // Short delay to ensure threads start in correct order
             try {
                 Thread.sleep(10);
             } catch (final InterruptedException e) {
                 fail(e.toString());
             }
         }
 
         // Return objects, other threads should get served in order
         for (int i = 0; i < maxTotal; i++) {
             genericObjectPool.returnObject(objects[i]);
         }
 
         // Wait for threads to finish
         for (int i = 0; i < numThreads; i++) {
             while (!threads[i].complete()) {
                 Waiter.sleepQuietly(500L);
             }
             if (threads[i].failed()) {
                 fail("Thread " + i + " failed: " + threads[i].error.toString());
             }
         }
     }
 
     @Test
     @Timeout(value = 1200, unit = TimeUnit.MILLISECONDS)
     public void testBorrowObjectOverrideMaxWaitLarge() throws Exception {
         try (final GenericObjectPool<String> pool = new GenericObjectPool<>(createSlowObjectFactory(Duration.ofSeconds(60)))) {
             pool.setMaxTotal(1);
             pool.setMaxWait(Duration.ofMillis(1_000)); // large
             pool.setBlockWhenExhausted(false);
             // thread1 tries creating a slow object to make pool full.
             final WaitingTestThread thread1 = new WaitingTestThread(pool, 0);
             thread1.start();
             // Wait for thread1's reaching to create().
             Thread.sleep(100);
             // The test needs to make sure a wait happens in create().
             final Duration d = DurationUtils.of(() -> assertThrows(NoSuchElementException.class, () -> pool.borrowObject(Duration.ofMillis(1)),
                     "borrowObject must fail quickly due to timeout parameter"));
             final long millis = d.toMillis();
             final long nanos = d.toNanos();
             assertTrue(nanos >= 0, () -> "borrowObject(Duration) argument not respected: " + nanos);
             assertTrue(millis >= 0, () -> "borrowObject(Duration) argument not respected: " + millis); // not > 0 to account for spurious waits
             assertTrue(millis < 50, () -> "borrowObject(Duration) argument not respected: " + millis);
         }
     }
 
     @Test
     @Timeout(value = 1200, unit = TimeUnit.MILLISECONDS)
     public void testBorrowObjectOverrideMaxWaitSmall() throws Exception {
         try (final GenericObjectPool<String> pool = new GenericObjectPool<>(createSlowObjectFactory(Duration.ofSeconds(60)))) {
             pool.setMaxTotal(1);
             pool.setMaxWait(Duration.ofMillis(1)); // small
             pool.setBlockWhenExhausted(false);
             // thread1 tries creating a slow object to make pool full.
             final WaitingTestThread thread1 = new WaitingTestThread(pool, 0);
             thread1.start();
             // Wait for thread1's reaching to create().
             Thread.sleep(100);
             // The test needs to make sure a wait happens in create().
             final Duration d = DurationUtils.of(() -> assertThrows(NoSuchElementException.class, () -> pool.borrowObject(Duration.ofMillis(500)),
                     "borrowObject must fail slowly due to timeout parameter"));
             final long millis = d.toMillis();
             final long nanos = d.toNanos();
             assertTrue(nanos >= 0, () -> "borrowObject(Duration) argument not respected: " + nanos);
             assertTrue(millis >= 0, () -> "borrowObject(Duration) argument not respected: " + millis); // not > 0 to account for spurious waits
             assertTrue(millis < 600, () -> "borrowObject(Duration) argument not respected: " + millis);
             assertTrue(millis > 490, () -> "borrowObject(Duration) argument not respected: " + millis);
         }
     }
 
     @Test
     public void testBorrowTimings() throws Exception {
         // Borrow
         final String object = genericObjectPool.borrowObject();
         final PooledObject<String> po = genericObjectPool.getPooledObject(object);
         // In the initial state, all instants are the creation instant: last borrow, last use, last return.
         // In the initial state, the active duration is the time between "now" and the creation time.
         // In the initial state, the idle duration is the time between "now" and the last return, which is the creation time.
         // But... this PO might have already been used in other tests in this class.
 
         final Instant lastBorrowInstant1 = po.getLastBorrowInstant();
         final Instant lastReturnInstant1 = po.getLastReturnInstant();
         final Instant lastUsedInstant1 = po.getLastUsedInstant();
 
         assertTrue(po.getCreateInstant().compareTo(lastBorrowInstant1) <= 0);
         assertTrue(po.getCreateInstant().compareTo(lastReturnInstant1) <= 0);
         assertTrue(po.getCreateInstant().compareTo(lastUsedInstant1) <= 0);
         // Deprecated
         assertTrue(po.getCreateTime() <= lastBorrowInstant1.toEpochMilli());
         assertTrue(po.getCreateTime() <= lastReturnInstant1.toEpochMilli());
         assertTrue(po.getCreateTime() <= lastUsedInstant1.toEpochMilli());
 
         // Sleep MUST be "long enough" to detect that more than 0 milliseconds have elapsed.
         // Need an API in Java 8 to get the clock granularity.
         Thread.sleep(200);
 
         assertFalse(po.getActiveDuration().isNegative());
         assertFalse(po.getActiveDuration().isZero());
         // We use greaterThanOrEqualTo instead of equal because "now" many be different when each argument is evaluated.
         assertTrue(Duration.ZERO.compareTo(Duration.ZERO.plusNanos(1)) <= 0); // sanity check
         assertTrue(po.getActiveDuration().compareTo(po.getIdleDuration()) <= 0);
         // Deprecated
         assertTrue(po.getActiveDuration().toMillis() <= po.getActiveTimeMillis());
         assertTrue(po.getActiveDuration().compareTo(po.getIdleDuration()) <= 0);
         //
         // TODO How to compare ID with AD since other tests may have touched the PO?
         assertTrue(po.getActiveDuration().compareTo(po.getIdleTime()) <= 0);
         assertTrue(po.getActiveDuration().toMillis() <= po.getIdleTimeMillis());
         //
         assertTrue(po.getCreateInstant().compareTo(po.getLastBorrowInstant()) <= 0);
         assertTrue(po.getCreateInstant().compareTo(po.getLastReturnInstant()) <= 0);
         assertTrue(po.getCreateInstant().compareTo(po.getLastUsedInstant()) <= 0);
 
         assertTrue(lastBorrowInstant1.compareTo(po.getLastBorrowInstant()) <= 0);
         assertTrue(lastReturnInstant1.compareTo(po.getLastReturnInstant()) <= 0);
         assertTrue(lastUsedInstant1.compareTo(po.getLastUsedInstant()) <= 0);
 
         genericObjectPool.returnObject(object);
 
         assertFalse(po.getActiveDuration().isNegative());
         assertFalse(po.getActiveDuration().isZero());
         assertTrue(po.getActiveDuration().toMillis() <= po.getActiveTimeMillis());
         assertTrue(po.getActiveDuration().compareTo(po.getActiveTime()) <= 0);
 
         assertTrue(lastBorrowInstant1.compareTo(po.getLastBorrowInstant()) <= 0);
         assertTrue(lastReturnInstant1.compareTo(po.getLastReturnInstant()) <= 0);
         assertTrue(lastUsedInstant1.compareTo(po.getLastUsedInstant()) <= 0);
     }
 
     /**
      * On first borrow, first object fails validation, second object is OK.
      * Subsequent borrows are OK. This was POOL-152.
      * @throws Exception
      */
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testBrokenFactoryShouldNotBlockPool() throws Exception {
         final int maxTotal = 1;
 
         simpleFactory.setMaxTotal(maxTotal);
         genericObjectPool.setMaxTotal(maxTotal);
         genericObjectPool.setBlockWhenExhausted(true);
         genericObjectPool.setTestOnBorrow(true);
 
         // First borrow object will need to create a new object which will fail
         // validation.
         String obj = null;
         Exception ex = null;
         simpleFactory.setValid(false);
         try {
             obj = genericObjectPool.borrowObject();
         } catch (final Exception e) {
             ex = e;
         }
         // Failure expected
         assertNotNull(ex);
         assertInstanceOf(NoSuchElementException.class, ex);
         assertNull(obj);
 
         // Configure factory to create valid objects so subsequent borrows work
         simpleFactory.setValid(true);
 
         // Subsequent borrows should be OK
         obj = genericObjectPool.borrowObject();
         assertNotNull(obj);
         genericObjectPool.returnObject(obj);
     }
 
     // POOL-259
     @Test
     public void testClientWaitStats() throws Exception {
         final SimpleFactory factory = new SimpleFactory();
         // Give makeObject a little latency
         factory.setMakeLatency(200);
         try (final GenericObjectPool<String> pool = new GenericObjectPool<>(factory, new GenericObjectPoolConfig<>())) {
             final String s = pool.borrowObject();
             // First borrow waits on create, so wait time should be at least 200 ms
             // Allow 100ms error in clock times
             assertTrue(pool.getMaxBorrowWaitTimeMillis() >= 100);
             assertTrue(pool.getMeanBorrowWaitTimeMillis() >= 100);
             pool.returnObject(s);
             pool.borrowObject();
             // Second borrow does not have to wait on create, average should be about 100
             assertTrue(pool.getMaxBorrowWaitTimeMillis() > 100);
             assertTrue(pool.getMeanBorrowWaitTimeMillis() < 200);
             assertTrue(pool.getMeanBorrowWaitTimeMillis() > 20);
         }
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testCloseMultiplePools1() {
         try (final GenericObjectPool<String> genericObjectPool2 = new GenericObjectPool<>(simpleFactory)) {
             genericObjectPool.setTimeBetweenEvictionRuns(TestConstants.ONE_MILLISECOND_DURATION);
             genericObjectPool2.setTimeBetweenEvictionRuns(TestConstants.ONE_MILLISECOND_DURATION);
         }
         genericObjectPool.close();
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testCloseMultiplePools2() throws Exception {
         try (final GenericObjectPool<String> genericObjectPool2 = new GenericObjectPool<>(simpleFactory)) {
             // Ensure eviction takes a long time, during which time EvictionTimer.executor's queue is empty
             simpleFactory.setDestroyLatency(1000L);
             // Ensure there is an object to evict, so that above latency takes effect
             genericObjectPool.setTimeBetweenEvictionRuns(TestConstants.ONE_MILLISECOND_DURATION);
             genericObjectPool2.setTimeBetweenEvictionRuns(TestConstants.ONE_MILLISECOND_DURATION);
             genericObjectPool.setMinEvictableIdleTime(TestConstants.ONE_MILLISECOND_DURATION);
             genericObjectPool2.setMinEvictableIdleTime(TestConstants.ONE_MILLISECOND_DURATION);
             genericObjectPool.addObject();
             genericObjectPool2.addObject();
             // Close both pools
         }
         genericObjectPool.close();
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testConcurrentBorrowAndEvict() throws Exception {
 
         genericObjectPool.setMaxTotal(1);
         genericObjectPool.addObject();
 
         for (int i = 0; i < 5000; i++) {
             final ConcurrentBorrowAndEvictThread one =
                     new ConcurrentBorrowAndEvictThread(true);
             final ConcurrentBorrowAndEvictThread two =
                     new ConcurrentBorrowAndEvictThread(false);
 
             one.start();
             two.start();
             one.join();
             two.join();
 
             genericObjectPool.returnObject(one.obj);
 
             /* Uncomment this for a progress indication
             if (i % 10 == 0) {
                 System.out.println(i/10);
             }
             */
         }
     }
 
     /**
      * POOL-231 - verify that concurrent invalidates of the same object do not
      * corrupt pool destroyCount.
      *
      * @throws Exception May occur in some failure modes
      */
     @Test
     public void testConcurrentInvalidate() throws Exception {
         // Get allObjects and idleObjects loaded with some instances
         final int nObjects = 1000;
         genericObjectPool.setMaxTotal(nObjects);
         genericObjectPool.setMaxIdle(nObjects);
         final String[] obj = new String[nObjects];
         for (int i = 0; i < nObjects; i++) {
             obj[i] = genericObjectPool.borrowObject();
         }
         for (int i = 0; i < nObjects; i++) {
             if (i % 2 == 0) {
                 genericObjectPool.returnObject(obj[i]);
             }
         }
         final int nThreads = 20;
         final int nIterations = 60;
         final InvalidateThread[] threads = new InvalidateThread[nThreads];
         // Randomly generated list of distinct invalidation targets
         final ArrayList<Integer> targets = new ArrayList<>();
         final Random random = new Random();
         for (int j = 0; j < nIterations; j++) {
             // Get a random invalidation target
             Integer targ = Integer.valueOf(random.nextInt(nObjects));
             while (targets.contains(targ)) {
                 targ = Integer.valueOf(random.nextInt(nObjects));
             }
             targets.add(targ);
             // Launch nThreads threads all trying to invalidate the target
             for (int i = 0; i < nThreads; i++) {
                 threads[i] = new InvalidateThread(genericObjectPool, obj[targ.intValue()]);
             }
             for (int i = 0; i < nThreads; i++) {
                 new Thread(threads[i]).start();
             }
             boolean done = false;
             while (!done) {
                 done = true;
                 for (int i = 0; i < nThreads; i++) {
                     done = done && threads[i].complete();
                 }
                 Thread.sleep(100);
             }
         }
         assertEquals(nIterations, genericObjectPool.getDestroyedCount());
     }
 
     @Test
     public void testConstructorNullFactory() {
         // add dummy assert (won't be invoked because of IAE) to avoid "unused" warning
         assertThrows(IllegalArgumentException.class,
                 () -> new GenericObjectPool<>(null));
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testConstructors() {
 
         // Make constructor arguments all different from defaults
         final int minIdle = 2;
         final Duration maxWaitDuration = Duration.ofMillis(3);
         final long maxWaitMillis = maxWaitDuration.toMillis();
         final int maxIdle = 4;
         final int maxTotal = 5;
         final Duration minEvictableIdleDuration = Duration.ofMillis(6);
         final long minEvictableIdleMillis = minEvictableIdleDuration.toMillis();
         final int numTestsPerEvictionRun = 7;
         final boolean testOnBorrow = true;
         final boolean testOnReturn = true;
         final boolean testWhileIdle = true;
         final long timeBetweenEvictionRunsMillis = 8;
         final boolean blockWhenExhausted = false;
         final boolean lifo = false;
         final PooledObjectFactory<Object> dummyFactory = new DummyFactory();
         try (GenericObjectPool<Object> dummyPool = new GenericObjectPool<>(dummyFactory)) {
             assertEquals(GenericObjectPoolConfig.DEFAULT_MAX_IDLE, dummyPool.getMaxIdle());
             assertEquals(BaseObjectPoolConfig.DEFAULT_MAX_WAIT_MILLIS, dummyPool.getMaxWaitMillis());
             assertEquals(GenericObjectPoolConfig.DEFAULT_MIN_IDLE, dummyPool.getMinIdle());
             assertEquals(GenericObjectPoolConfig.DEFAULT_MAX_TOTAL, dummyPool.getMaxTotal());
             assertEquals(BaseObjectPoolConfig.DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS,
                     dummyPool.getMinEvictableIdleTimeMillis());
             assertEquals(BaseObjectPoolConfig.DEFAULT_MIN_EVICTABLE_IDLE_TIME,
                     dummyPool.getMinEvictableIdleTime());
             assertEquals(BaseObjectPoolConfig.DEFAULT_MIN_EVICTABLE_IDLE_TIME,
                     dummyPool.getMinEvictableIdleDuration());
             assertEquals(BaseObjectPoolConfig.DEFAULT_NUM_TESTS_PER_EVICTION_RUN,
                     dummyPool.getNumTestsPerEvictionRun());
             assertEquals(Boolean.valueOf(BaseObjectPoolConfig.DEFAULT_TEST_ON_BORROW),
                     Boolean.valueOf(dummyPool.getTestOnBorrow()));
             assertEquals(Boolean.valueOf(BaseObjectPoolConfig.DEFAULT_TEST_ON_RETURN),
                     Boolean.valueOf(dummyPool.getTestOnReturn()));
             assertEquals(Boolean.valueOf(BaseObjectPoolConfig.DEFAULT_TEST_WHILE_IDLE),
                     Boolean.valueOf(dummyPool.getTestWhileIdle()));
             assertEquals(BaseObjectPoolConfig.DEFAULT_DURATION_BETWEEN_EVICTION_RUNS,
                     dummyPool.getDurationBetweenEvictionRuns());
             assertEquals(BaseObjectPoolConfig.DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS,
                     dummyPool.getTimeBetweenEvictionRunsMillis());
             assertEquals(BaseObjectPoolConfig.DEFAULT_TIME_BETWEEN_EVICTION_RUNS,
                     dummyPool.getTimeBetweenEvictionRuns());
             assertEquals(Boolean.valueOf(BaseObjectPoolConfig.DEFAULT_BLOCK_WHEN_EXHAUSTED),
                     Boolean.valueOf(dummyPool.getBlockWhenExhausted()));
             assertEquals(Boolean.valueOf(BaseObjectPoolConfig.DEFAULT_LIFO), Boolean.valueOf(dummyPool.getLifo()));
         }
 
         final GenericObjectPoolConfig<Object> config = new GenericObjectPoolConfig<>();
         config.setLifo(lifo);
         config.setMaxIdle(maxIdle);
         config.setMinIdle(minIdle);
         config.setMaxTotal(maxTotal);
         config.setMaxWait(maxWaitDuration);
         config.setMinEvictableIdleTimeMillis(minEvictableIdleMillis);
         assertEquals(minEvictableIdleMillis, config.getMinEvictableIdleTime().toMillis());
         config.setNumTestsPerEvictionRun(numTestsPerEvictionRun);
         config.setTestOnBorrow(testOnBorrow);
         config.setTestOnReturn(testOnReturn);
         config.setTestWhileIdle(testWhileIdle);
         config.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
         assertEquals(timeBetweenEvictionRunsMillis, config.getTimeBetweenEvictionRuns().toMillis());
         config.setBlockWhenExhausted(blockWhenExhausted);
         try (GenericObjectPool<Object> dummyPool = new GenericObjectPool<>(dummyFactory, config)) {
             assertEquals(maxIdle, dummyPool.getMaxIdle());
             assertEquals(maxWaitDuration, dummyPool.getMaxWaitDuration());
             assertEquals(maxWaitMillis, dummyPool.getMaxWaitMillis());
             assertEquals(minIdle, dummyPool.getMinIdle());
             assertEquals(maxTotal, dummyPool.getMaxTotal());
             assertEquals(minEvictableIdleMillis, dummyPool.getMinEvictableIdleTimeMillis());
             assertEquals(numTestsPerEvictionRun, dummyPool.getNumTestsPerEvictionRun());
             assertEquals(Boolean.valueOf(testOnBorrow), Boolean.valueOf(dummyPool.getTestOnBorrow()));
             assertEquals(Boolean.valueOf(testOnReturn), Boolean.valueOf(dummyPool.getTestOnReturn()));
             assertEquals(Boolean.valueOf(testWhileIdle), Boolean.valueOf(dummyPool.getTestWhileIdle()));
             assertEquals(timeBetweenEvictionRunsMillis, dummyPool.getTimeBetweenEvictionRunsMillis());
             assertEquals(Boolean.valueOf(blockWhenExhausted), Boolean.valueOf(dummyPool.getBlockWhenExhausted()));
             assertEquals(Boolean.valueOf(lifo), Boolean.valueOf(dummyPool.getLifo()));
         }
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testDefaultConfiguration() {
         assertConfiguration(new GenericObjectPoolConfig<>(),genericObjectPool);
     }
 
     /**
      * Verifies that when a factory's makeObject produces instances that are not
      * discernible by equals, the pool can handle them.
      *
      * JIRA: POOL-283
      */
     @Test
     public void testEqualsIndiscernible() throws Exception {
         final HashSetFactory factory = new HashSetFactory();
         try (final GenericObjectPool<HashSet<String>> pool = new GenericObjectPool<>(factory,
                 new GenericObjectPoolConfig<>())) {
             final HashSet<String> s1 = pool.borrowObject();
             final HashSet<String> s2 = pool.borrowObject();
             pool.returnObject(s1);
             pool.returnObject(s2);
         }
     }
 
     @Test
     public void testErrorFactoryDoesNotBlockThreads() throws Exception {
 
         final CreateErrorFactory factory = new CreateErrorFactory();
         try (final GenericObjectPool<String> createFailFactoryPool = new GenericObjectPool<>(factory)) {
 
             createFailFactoryPool.setMaxTotal(1);
 
             // Try and borrow the first object from the pool
             final WaitingTestThread thread1 = new WaitingTestThread(createFailFactoryPool, 0);
             thread1.start();
 
             // Wait for thread to reach semaphore
             while (!factory.hasQueuedThreads()) {
                 Thread.sleep(200);
             }
 
             // Try and borrow the second object from the pool
             final WaitingTestThread thread2 = new WaitingTestThread(createFailFactoryPool, 0);
             thread2.start();
             // Pool will not call factory since maximum number of object creations
             // are already queued.
 
             // Thread 2 will wait on an object being returned to the pool
             // Give thread 2 a chance to reach this state
             Thread.sleep(1000);
 
             // Release thread1
             factory.release();
             // Pre-release thread2
             factory.release();
 
             // Both threads should now complete.
             boolean threadRunning = true;
             int count = 0;
             while (threadRunning && count < 15) {
                 threadRunning = thread1.isAlive();
                 threadRunning = thread2.isAlive();
                 Thread.sleep(200);
                 count++;
             }
             assertFalse(thread1.isAlive());
             assertFalse(thread2.isAlive());
 
             assertTrue(thread1.thrown instanceof UnknownError);
             assertTrue(thread2.thrown instanceof UnknownError);
         }
     }
 
     /**
      * Tests addObject contention between ensureMinIdle triggered by
      * the Evictor with minIdle &gt; 0 and borrowObject.
      *
      * @throws Exception May occur in some failure modes
      */
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testEvictAddObjects() throws Exception {
         simpleFactory.setMakeLatency(300);
         simpleFactory.setMaxTotal(2);
         genericObjectPool.setMaxTotal(2);
         genericObjectPool.setMinIdle(1);
         genericObjectPool.borrowObject(); // numActive = 1, numIdle = 0
         // Create a test thread that will run once and try a borrow after
         // 150ms fixed delay
         final TestThread<String> borrower = new TestThread<>(genericObjectPool, 1, 150, false);
         final Thread borrowerThread = new Thread(borrower);
         // Set evictor to run in 100 ms - will create idle instance
         genericObjectPool.setTimeBetweenEvictionRuns(Duration.ofMillis(100));
         borrowerThread.start();  // Off to the races
         borrowerThread.join();
         assertFalse(borrower.failed());
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testEvictFIFO() throws Exception {
         checkEvict(false);
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testEviction() throws Exception {
         genericObjectPool.setMaxIdle(500);
         genericObjectPool.setMaxTotal(500);
         genericObjectPool.setNumTestsPerEvictionRun(100);
         genericObjectPool.setMinEvictableIdleTime(Duration.ofMillis(250));
         genericObjectPool.setTimeBetweenEvictionRuns(Duration.ofMillis(500));
         genericObjectPool.setTestWhileIdle(true);
 
         final String[] active = new String[500];
         for (int i = 0; i < 500; i++) {
             active[i] = genericObjectPool.borrowObject();
         }
         for (int i = 0; i < 500; i++) {
             genericObjectPool.returnObject(active[i]);
         }
 
         Waiter.sleepQuietly(1000L);
         assertTrue(genericObjectPool.getNumIdle() < 500, "Should be less than 500 idle, found " + genericObjectPool.getNumIdle());
         Waiter.sleepQuietly(600L);
         assertTrue(genericObjectPool.getNumIdle() < 400, "Should be less than 400 idle, found " + genericObjectPool.getNumIdle());
         Waiter.sleepQuietly(600L);
         assertTrue(genericObjectPool.getNumIdle() < 300, "Should be less than 300 idle, found " + genericObjectPool.getNumIdle());
         Waiter.sleepQuietly(600L);
         assertTrue(genericObjectPool.getNumIdle() < 200, "Should be less than 200 idle, found " + genericObjectPool.getNumIdle());
         Waiter.sleepQuietly(600L);
         assertTrue(genericObjectPool.getNumIdle() < 100, "Should be less than 100 idle, found " + genericObjectPool.getNumIdle());
         Waiter.sleepQuietly(600L);
         assertEquals(0, genericObjectPool.getNumIdle(), "Should be zero idle, found " + genericObjectPool.getNumIdle());
 
         for (int i = 0; i < 500; i++) {
             active[i] = genericObjectPool.borrowObject();
         }
         for (int i = 0; i < 500; i++) {
             genericObjectPool.returnObject(active[i]);
         }
 
         Waiter.sleepQuietly(1000L);
         assertTrue(genericObjectPool.getNumIdle() < 500, "Should be less than 500 idle, found " + genericObjectPool.getNumIdle());
         Waiter.sleepQuietly(600L);
         assertTrue(genericObjectPool.getNumIdle() < 400, "Should be less than 400 idle, found " + genericObjectPool.getNumIdle());
         Waiter.sleepQuietly(600L);
         assertTrue(genericObjectPool.getNumIdle() < 300, "Should be less than 300 idle, found " + genericObjectPool.getNumIdle());
         Waiter.sleepQuietly(600L);
         assertTrue(genericObjectPool.getNumIdle() < 200, "Should be less than 200 idle, found " + genericObjectPool.getNumIdle());
         Waiter.sleepQuietly(600L);
         assertTrue(genericObjectPool.getNumIdle() < 100, "Should be less than 100 idle, found " + genericObjectPool.getNumIdle());
         Waiter.sleepQuietly(600L);
         assertEquals(0, genericObjectPool.getNumIdle(), "Should be zero idle, found " + genericObjectPool.getNumIdle());
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testEvictionInvalid() throws Exception {
 
         try (final GenericObjectPool<Object> invalidFactoryPool = new GenericObjectPool<>(new InvalidFactory())) {
 
             invalidFactoryPool.setMaxIdle(1);
             invalidFactoryPool.setMaxTotal(1);
             invalidFactoryPool.setTestOnBorrow(false);
             invalidFactoryPool.setTestOnReturn(false);
             invalidFactoryPool.setTestWhileIdle(true);
             invalidFactoryPool.setMinEvictableIdleTime(Duration.ofSeconds(100));
             invalidFactoryPool.setNumTestsPerEvictionRun(1);
 
             final Object p = invalidFactoryPool.borrowObject();
             invalidFactoryPool.returnObject(p);
 
             // Run eviction in a separate thread
             final Thread t = new EvictionThread<>(invalidFactoryPool);
             t.start();
 
             // Sleep to make sure evictor has started
             Thread.sleep(300);
 
             try {
                 invalidFactoryPool.borrowObject(1);
             } catch (final NoSuchElementException nsee) {
                 // Ignore
             }
 
             // Make sure evictor has finished
             Thread.sleep(1000);
 
             // Should have an empty pool
             assertEquals(0, invalidFactoryPool.getNumIdle(), "Idle count different than expected.");
             assertEquals(0, invalidFactoryPool.getNumActive(), "Total count different than expected.");
         }
     }
 
     /**
      * Test to make sure evictor visits least recently used objects first,
      * regardless of FIFO/LIFO.
      *
      * JIRA: POOL-86
      *
      * @throws Exception May occur in some failure modes
      */
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testEvictionOrder() throws Exception {
         checkEvictionOrder(false);
         tearDown();
         setUp();
         checkEvictionOrder(true);
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testEvictionPolicy() throws Exception {
         genericObjectPool.setMaxIdle(500);
         genericObjectPool.setMaxTotal(500);
         genericObjectPool.setNumTestsPerEvictionRun(500);
         genericObjectPool.setMinEvictableIdleTime(Duration.ofMillis(250));
         genericObjectPool.setTimeBetweenEvictionRuns(Duration.ofMillis(500));
         genericObjectPool.setTestWhileIdle(true);
 
         // ClassNotFoundException
         assertThrows(IllegalArgumentException.class, () -> genericObjectPool.setEvictionPolicyClassName(Long.toString(System.currentTimeMillis())),
                 "setEvictionPolicyClassName must throw an error if the class name is invalid.");
 
         // InstantiationException
         assertThrows(IllegalArgumentException.class, () -> genericObjectPool.setEvictionPolicyClassName(java.io.Serializable.class.getName()),
                 "setEvictionPolicyClassName must throw an error if the class name is invalid.");
 
         // IllegalAccessException
         assertThrows(IllegalArgumentException.class, () -> genericObjectPool.setEvictionPolicyClassName(java.util.Collections.class.getName()),
                 "setEvictionPolicyClassName must throw an error if the class name is invalid.");
 
         assertThrows(IllegalArgumentException.class, () -> genericObjectPool.setEvictionPolicyClassName(java.lang.String.class.getName()),
                 () -> "setEvictionPolicyClassName must throw an error if a class that does not implement EvictionPolicy is specified.");
 
         genericObjectPool.setEvictionPolicy(new TestEvictionPolicy<>());
         assertEquals(TestEvictionPolicy.class.getName(), genericObjectPool.getEvictionPolicyClassName());
 
         genericObjectPool.setEvictionPolicyClassName(TestEvictionPolicy.class.getName());
         assertEquals(TestEvictionPolicy.class.getName(), genericObjectPool.getEvictionPolicyClassName());
 
         final String[] active = new String[500];
         for (int i = 0; i < 500; i++) {
             active[i] = genericObjectPool.borrowObject();
         }
         for (int i = 0; i < 500; i++) {
             genericObjectPool.returnObject(active[i]);
         }
 
         // Eviction policy ignores first 1500 attempts to evict and then always
         // evicts. After 1s, there should have been two runs of 500 tests so no
         // evictions
         Waiter.sleepQuietly(1000L);
         assertEquals(500, genericObjectPool.getNumIdle(), "Should be 500 idle");
         // A further 1s wasn't enough so allow 2s for the evictor to clear out
         // all of the idle objects.
         Waiter.sleepQuietly(2000L);
         assertEquals(0, genericObjectPool.getNumIdle(), "Should be 0 idle");
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testEvictionSoftMinIdle() throws Exception {
         final class TimeTest extends BasePooledObjectFactory<TimeTest> {
             private final long createTimeMillis;
 
             public TimeTest() {
                 createTimeMillis = System.currentTimeMillis();
             }
 
             @Override
             public TimeTest create() {
                 return new TimeTest();
             }
 
             public long getCreateTimeMillis() {
                 return createTimeMillis;
             }
 
             @Override
             public PooledObject<TimeTest> wrap(final TimeTest value) {
                 return new DefaultPooledObject<>(value);
             }
         }
 
         try (final GenericObjectPool<TimeTest> timePool = new GenericObjectPool<>(new TimeTest())) {
 
             timePool.setMaxIdle(5);
             timePool.setMaxTotal(5);
             timePool.setNumTestsPerEvictionRun(5);
             timePool.setMinEvictableIdleDuration(Duration.ofSeconds(3));
             timePool.setMinEvictableIdle(Duration.ofSeconds(3));
             timePool.setMinEvictableIdleTime(Duration.ofSeconds(3));
             timePool.setSoftMinEvictableIdleTime(TestConstants.ONE_SECOND_DURATION);
             timePool.setMinIdle(2);
 
             final TimeTest[] active = new TimeTest[5];
             final Long[] creationTime = new Long[5];
             for (int i = 0; i < 5; i++) {
                 active[i] = timePool.borrowObject();
                 creationTime[i] = Long.valueOf(active[i].getCreateTimeMillis());
             }
 
             for (int i = 0; i < 5; i++) {
                 timePool.returnObject(active[i]);
             }
 
             // Soft evict all but minIdle(2)
             Thread.sleep(1500L);
             timePool.evict();
             assertEquals(2, timePool.getNumIdle(), "Idle count different than expected.");
 
             // Hard evict the rest.
             Thread.sleep(2000L);
             timePool.evict();
             assertEquals(0, timePool.getNumIdle(), "Idle count different than expected.");
         }
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testEvictionWithNegativeNumTests() throws Exception {
         // when numTestsPerEvictionRun is negative, it represents a fraction of the idle objects to test
         genericObjectPool.setMaxIdle(6);
         genericObjectPool.setMaxTotal(6);
         genericObjectPool.setNumTestsPerEvictionRun(-2);
         genericObjectPool.setMinEvictableIdleTime(Duration.ofMillis(50));
         genericObjectPool.setTimeBetweenEvictionRuns(Duration.ofMillis(100));
 
         final String[] active = new String[6];
         for (int i = 0; i < 6; i++) {
             active[i] = genericObjectPool.borrowObject();
         }
         for (int i = 0; i < 6; i++) {
             genericObjectPool.returnObject(active[i]);
         }
 
         Waiter.sleepQuietly(100L);
         assertTrue(genericObjectPool.getNumIdle() <= 6, "Should at most 6 idle, found " + genericObjectPool.getNumIdle());
         Waiter.sleepQuietly(100L);
         assertTrue(genericObjectPool.getNumIdle() <= 3, "Should at most 3 idle, found " + genericObjectPool.getNumIdle());
         Waiter.sleepQuietly(100L);
         assertTrue(genericObjectPool.getNumIdle() <= 2, "Should be at most 2 idle, found " + genericObjectPool.getNumIdle());
         Waiter.sleepQuietly(100L);
         assertEquals(0, genericObjectPool.getNumIdle(), "Should be zero idle, found " + genericObjectPool.getNumIdle());
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testEvictLIFO() throws Exception {
         checkEvict(true);
     }
 
     /**
      * Verifies that the evictor visits objects in expected order
      * and frequency.
      *
      * @throws Exception May occur in some failure modes
      */
     @Test
     public void testEvictorVisiting() throws Exception {
         checkEvictorVisiting(true);
         checkEvictorVisiting(false);
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testEvictWhileEmpty() throws Exception {
         genericObjectPool.evict();
         genericObjectPool.evict();
         genericObjectPool.close();
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testExceptionInValidationDuringEviction() throws Exception {
         genericObjectPool.setMaxIdle(1);
         genericObjectPool.setMinEvictableIdleTime(Duration.ZERO);
         genericObjectPool.setTestWhileIdle(true);
 
         final String active = genericObjectPool.borrowObject();
         genericObjectPool.returnObject(active);
 
         simpleFactory.setThrowExceptionOnValidate(true);
 
         assertThrows(RuntimeException.class, () -> genericObjectPool.evict());
         assertEquals(0, genericObjectPool.getNumActive());
         assertEquals(0, genericObjectPool.getNumIdle());
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testExceptionOnActivateDuringBorrow() throws Exception {
         final String obj1 = genericObjectPool.borrowObject();
         final String obj2 = genericObjectPool.borrowObject();
         genericObjectPool.returnObject(obj1);
         genericObjectPool.returnObject(obj2);
         simpleFactory.setThrowExceptionOnActivate(true);
         simpleFactory.setEvenValid(false);
         // Activation will now throw every other time
         // First attempt throws, but loop continues and second succeeds
         final String obj = genericObjectPool.borrowObject();
         assertEquals(1, genericObjectPool.getNumActive());
         assertEquals(0, genericObjectPool.getNumIdle());
 
         genericObjectPool.returnObject(obj);
         simpleFactory.setValid(false);
         // Validation will now fail on activation when borrowObject returns
         // an idle instance, and then when attempting to create a new instance
         assertThrows(NoSuchElementException.class, () -> genericObjectPool.borrowObject());
         assertEquals(0, genericObjectPool.getNumActive());
         assertEquals(0, genericObjectPool.getNumIdle());
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testExceptionOnDestroyDuringBorrow() throws Exception {
         simpleFactory.setThrowExceptionOnDestroy(true);
         genericObjectPool.setTestOnBorrow(true);
         genericObjectPool.borrowObject();
         simpleFactory.setValid(false); // Make validation fail on next borrow attempt
         assertThrows(NoSuchElementException.class, () -> genericObjectPool.borrowObject());
         assertEquals(1, genericObjectPool.getNumActive());
         assertEquals(0, genericObjectPool.getNumIdle());
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testExceptionOnDestroyDuringReturn() throws Exception {
         simpleFactory.setThrowExceptionOnDestroy(true);
         genericObjectPool.setTestOnReturn(true);
         final String obj1 = genericObjectPool.borrowObject();
         genericObjectPool.borrowObject();
         simpleFactory.setValid(false); // Make validation fail
         genericObjectPool.returnObject(obj1);
         assertEquals(1, genericObjectPool.getNumActive());
         assertEquals(0, genericObjectPool.getNumIdle());
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testExceptionOnPassivateDuringReturn() throws Exception {
         final String obj = genericObjectPool.borrowObject();
         simpleFactory.setThrowExceptionOnPassivate(true);
         genericObjectPool.returnObject(obj);
         assertEquals(0,genericObjectPool.getNumIdle());
     }
 
     @Test
     public void testFailingFactoryDoesNotBlockThreads() throws Exception {
 
         final CreateFailFactory factory = new CreateFailFactory();
         try (final GenericObjectPool<String> createFailFactoryPool = new GenericObjectPool<>(factory)) {
 
             createFailFactoryPool.setMaxTotal(1);
 
             // Try and borrow the first object from the pool
             final WaitingTestThread thread1 = new WaitingTestThread(createFailFactoryPool, 0);
             thread1.start();
 
             // Wait for thread to reach semaphore
             while (!factory.hasQueuedThreads()) {
                 Thread.sleep(200);
             }
 
             // Try and borrow the second object from the pool
             final WaitingTestThread thread2 = new WaitingTestThread(createFailFactoryPool, 0);
             thread2.start();
             // Pool will not call factory since maximum number of object creations
             // are already queued.
 
             // Thread 2 will wait on an object being returned to the pool
             // Give thread 2 a chance to reach this state
             Thread.sleep(1000);
 
             // Release thread1
             factory.release();
             // Pre-release thread2
             factory.release();
 
             // Both threads should now complete.
             boolean threadRunning = true;
             int count = 0;
             while (threadRunning && count < 15) {
                 threadRunning = thread1.isAlive();
                 threadRunning = thread2.isAlive();
                 Thread.sleep(200);
                 count++;
             }
             assertFalse(thread1.isAlive());
             assertFalse(thread2.isAlive());
 
             assertTrue(thread1.thrown instanceof UnsupportedCharsetException);
             assertTrue(thread2.thrown instanceof UnsupportedCharsetException);
         }
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testFIFO() throws Exception {
         genericObjectPool.setLifo(false);
         genericObjectPool.addObject(); // "0"
         genericObjectPool.addObject(); // "1"
         genericObjectPool.addObject(); // "2"
         assertEquals("0", genericObjectPool.borrowObject(), "Oldest");
         assertEquals("1", genericObjectPool.borrowObject(), "Middle");
         assertEquals("2", genericObjectPool.borrowObject(), "Youngest");
         final String o = genericObjectPool.borrowObject();
         assertEquals("3", o, "new-3");
         genericObjectPool.returnObject(o);
         assertEquals(o, genericObjectPool.borrowObject(), "returned-3");
         assertEquals("4", genericObjectPool.borrowObject(), "new-4");
     }
 
     @Test
     public void testGetFactoryType_DefaultPooledObjectFactory() {
         try (final GenericObjectPool<String> pool = new GenericObjectPool<>(createDefaultPooledObjectFactory())) {
             assertNotNull(pool.getFactoryType());
         }
     }
 
     @Test
     public void testGetFactoryType_NullPooledObjectFactory() {
         try (final GenericObjectPool<String> pool = new GenericObjectPool<>(createNullPooledObjectFactory())) {
             assertNotNull(pool.getFactoryType());
         }
     }
 
     @Test
     public void testGetFactoryType_PoolUtilsSynchronizedDefaultPooledFactory() {
         try (final GenericObjectPool<String> pool = new GenericObjectPool<>(
                 PoolUtils.synchronizedPooledFactory(createDefaultPooledObjectFactory()))) {
             assertNotNull(pool.getFactoryType());
         }
     }
 
     @Test
     public void testGetFactoryType_PoolUtilsSynchronizedNullPooledFactory() {
         try (final GenericObjectPool<String> pool = new GenericObjectPool<>(
                 PoolUtils.synchronizedPooledFactory(createNullPooledObjectFactory()))) {
             assertNotNull(pool.getFactoryType());
         }
     }
 
     @Test
     public void testGetFactoryType_SynchronizedDefaultPooledObjectFactory() {
         try (final GenericObjectPool<String> pool = new GenericObjectPool<>(
                 new TestSynchronizedPooledObjectFactory<>(createDefaultPooledObjectFactory()))) {
             assertNotNull(pool.getFactoryType());
         }
     }
 
     @Test
     public void testGetFactoryType_SynchronizedNullPooledObjectFactory() {
         try (final GenericObjectPool<String> pool = new GenericObjectPool<>(
                 new TestSynchronizedPooledObjectFactory<>(createNullPooledObjectFactory()))) {
             assertNotNull(pool.getFactoryType());
         }
     }
 
     @Test
     public void testGetStatsString() {
         try (final GenericObjectPool<String> pool = new GenericObjectPool<>(
                 new TestSynchronizedPooledObjectFactory<>(createNullPooledObjectFactory()))) {
             assertNotNull(pool.getStatsString());
         }
     }
 
     /**
      * Verify that threads waiting on a depleted pool get served when a checked out object is
      * invalidated.
      *
      * JIRA: POOL-240
      *
      * @throws Exception May occur in some failure modes
      */
     @Test
     public void testInvalidateFreesCapacity() throws Exception {
         final SimpleFactory factory = new SimpleFactory();
         try (final GenericObjectPool<String> pool = new GenericObjectPool<>(factory)) {
             pool.setMaxTotal(2);
             pool.setMaxWaitMillis(500);
             // Borrow an instance and hold if for 5 seconds
             final WaitingTestThread thread1 = new WaitingTestThread(pool, 5000);
             thread1.start();
             // Borrow another instance
             final String obj = pool.borrowObject();
             // Launch another thread - will block, but fail in 500 ms
             final WaitingTestThread thread2 = new WaitingTestThread(pool, 100);
             thread2.start();
             // Invalidate the object borrowed by this thread - should allow thread2 to create
             Thread.sleep(20);
             pool.invalidateObject(obj);
             Thread.sleep(600); // Wait for thread2 to timeout
             if (thread2.thrown != null) {
                 fail(thread2.thrown.toString());
             }
         }
     }
 
     /**
      * Ensure the pool is registered.
      */
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testJmxRegistration() {
         final ObjectName oname = genericObjectPool.getJmxName();
         final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
         final Set<ObjectName> result = mbs.queryNames(oname, null);
         assertEquals(1, result.size());
         genericObjectPool.jmxUnregister();
 
         final GenericObjectPoolConfig<String> config = new GenericObjectPoolConfig<>();
         config.setJmxEnabled(false);
         try (final GenericObjectPool<String> poolWithoutJmx = new GenericObjectPool<>(simpleFactory, config)) {
             assertNull(poolWithoutJmx.getJmxName());
             config.setJmxEnabled(true);
             poolWithoutJmx.jmxUnregister();
         }
 
         config.setJmxNameBase(null);
         try (final GenericObjectPool<String> poolWithDefaultJmxNameBase = new GenericObjectPool<>(simpleFactory, config)) {
             assertNotNull(poolWithDefaultJmxNameBase.getJmxName());
         }
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testLIFO() throws Exception {
         final String o;
         genericObjectPool.setLifo(true);
         genericObjectPool.addObject(); // "0"
         genericObjectPool.addObject(); // "1"
         genericObjectPool.addObject(); // "2"
         assertEquals("2", genericObjectPool.borrowObject(), "Youngest");
         assertEquals("1", genericObjectPool.borrowObject(), "Middle");
         assertEquals("0", genericObjectPool.borrowObject(), "Oldest");
         o = genericObjectPool.borrowObject();
         assertEquals("3", o, "new-3");
         genericObjectPool.returnObject(o);
         assertEquals(o, genericObjectPool.borrowObject(), "returned-3");
         assertEquals("4", genericObjectPool.borrowObject(), "new-4");
     }
 
     /**
      * Simplest example of recovery from factory outage.
      * A thread gets into parked wait on the deque when there is capacity to create, but
      * creates are failing due to factory outage.  Verify that the borrower is served
      * once the factory is back online.
      */
     @Test
     @Disabled
     @Timeout(value = 1000, unit = TimeUnit.MILLISECONDS)
     public void testLivenessOnTransientFactoryFailure() throws Exception {
         final DisconnectingWaiterFactory<String> factory = new DisconnectingWaiterFactory<>(
             DisconnectingWaiterFactory.DEFAULT_DISCONNECTED_CREATE_ACTION,
             DisconnectingWaiterFactory.DEFAULT_DISCONNECTED_LIFECYCLE_ACTION,
             obj -> false // all instances fail validation
         );
         final GenericObjectPool<Waiter> pool = new GenericObjectPool<>(factory);
         pool.setMaxWait(Duration.ofMillis(100));
         pool.setTestOnReturn(true);
         pool.setMaxTotal(1);
         final Waiter w = pool.borrowObject();
         final AtomicBoolean failed = new AtomicBoolean();
         final Thread t = new Thread(() -> {
             try {
                 pool.borrowObject();
             } catch (final Exception e) {
                 failed.set(true);
             }
         });
         Thread.sleep(10);
         t.start();
         // t is blocked waiting on the deque
         Thread.sleep(10);
         factory.disconnect();
         pool.returnObject(w);  // validation fails, so no return
         Thread.sleep(10);
         factory.connect();
         // Borrower should be able to be served now
         t.join();
         pool.close();
         if (failed.get()) {
             fail("Borrower timed out waiting for an instance");
         }
     }
 
     /**
      * Test the following scenario:
      *   Thread 1 borrows an instance
      *   Thread 2 starts to borrow another instance before thread 1 returns its instance
      *   Thread 1 returns its instance while thread 2 is validating its newly created instance
      * The test verifies that the instance created by Thread 2 is not leaked.
      *
      * @throws Exception May occur in some failure modes
      */
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testMakeConcurrentWithReturn() throws Exception {
         genericObjectPool.setTestOnBorrow(true);
         simpleFactory.setValid(true);
         // Borrow and return an instance, with a short wait
         final WaitingTestThread thread1 = new WaitingTestThread(genericObjectPool, 200);
         thread1.start();
         Thread.sleep(50); // wait for validation to succeed
         // Slow down validation and borrow an instance
         simpleFactory.setValidateLatency(400);
         final String instance = genericObjectPool.borrowObject();
         // Now make sure that we have not leaked an instance
         assertEquals(simpleFactory.getMakeCounter(), genericObjectPool.getNumIdle() + 1);
         genericObjectPool.returnObject(instance);
         assertEquals(simpleFactory.getMakeCounter(), genericObjectPool.getNumIdle());
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testMaxIdle() throws Exception {
         genericObjectPool.setMaxTotal(100);
         genericObjectPool.setMaxIdle(8);
         final String[] active = new String[100];
         for (int i = 0; i < 100; i++) {
             active[i] = genericObjectPool.borrowObject();
         }
         assertEquals(100, genericObjectPool.getNumActive());
         assertEquals(0, genericObjectPool.getNumIdle());
         for (int i = 0; i < 100; i++) {
             genericObjectPool.returnObject(active[i]);
             assertEquals(99 - i, genericObjectPool.getNumActive());
             assertEquals(i < 8 ? i + 1 : 8, genericObjectPool.getNumIdle());
         }
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testMaxIdleZero() throws Exception {
         genericObjectPool.setMaxTotal(100);
         genericObjectPool.setMaxIdle(0);
         final String[] active = new String[100];
         for (int i = 0; i < 100; i++) {
             active[i] = genericObjectPool.borrowObject();
         }
         assertEquals(100, genericObjectPool.getNumActive());
         assertEquals(0, genericObjectPool.getNumIdle());
         for (int i = 0; i < 100; i++) {
             genericObjectPool.returnObject(active[i]);
             assertEquals(99 - i, genericObjectPool.getNumActive());
             assertEquals(0, genericObjectPool.getNumIdle());
         }
     }
 
     /**
      * Showcasing a possible deadlock situation as reported in POOL-356
      */
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     @SuppressWarnings("rawtypes")
     public void testMaxIdleZeroUnderLoad() {
         // Config
         final int numThreads = 199; // And main thread makes a round 200.
         final int numIter = 20;
         final int delay = 25;
         final int maxTotal = 10;
 
         simpleFactory.setMaxTotal(maxTotal);
         genericObjectPool.setMaxTotal(maxTotal);
         genericObjectPool.setBlockWhenExhausted(true);
         genericObjectPool.setTimeBetweenEvictionRuns(Duration.ofMillis(-1));
 
         // this is important to trigger POOL-356
         genericObjectPool.setMaxIdle(0);
 
         // Start threads to borrow objects
         final TestThread[] threads = new TestThread[numThreads];
         for(int i=0;i<numThreads;i++) {
             // Factor of 2 on iterations so main thread does work whilst other
             // threads are running. Factor of 2 on delay so average delay for
             // other threads == actual delay for main thread
             threads[i] = new TestThread<>(genericObjectPool, numIter * 2, delay * 2);
             final Thread t = new Thread(threads[i]);
             t.start();
         }
         // Give the threads a chance to start doing some work
         Waiter.sleepQuietly(100L);
 
         for (int i = 0; i < numIter; i++) {
             String obj = null;
             try {
                 Waiter.sleepQuietly(delay);
                 obj = genericObjectPool.borrowObject();
                 // Under load, observed numActive > maxTotal
                 if (genericObjectPool.getNumActive() > genericObjectPool.getMaxTotal()) {
                     throw new IllegalStateException("Too many active objects");
                 }
                 Waiter.sleepQuietly(delay);
             } catch (final Exception e) {
                 // Shouldn't happen
                 e.printStackTrace();
                 fail("Exception on borrow");
             } finally {
                 if (obj != null) {
                     try {
                         genericObjectPool.returnObject(obj);
                     } catch (final Exception e) {
                         // Ignore
                     }
                 }
             }
         }
 
         for (int i = 0; i < numThreads; i++) {
             while (!threads[i].complete()) {
                 Waiter.sleepQuietly(500L);
             }
             if (threads[i].failed()) {
                 threads[i].error.printStackTrace();
                 fail("Thread " + i + " failed: " + threads[i].error.toString());
             }
         }
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testMaxTotal() throws Exception {
         genericObjectPool.setMaxTotal(3);
         genericObjectPool.setBlockWhenExhausted(false);
 
         genericObjectPool.borrowObject();
         genericObjectPool.borrowObject();
         genericObjectPool.borrowObject();
         assertThrows(NoSuchElementException.class, () -> genericObjectPool.borrowObject());
     }
 
     /**
      * Verifies that maxTotal is not exceeded when factory destroyObject
      * has high latency, testOnReturn is set and there is high incidence of
      * validation failures.
      */
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testMaxTotalInvariant() {
         final int maxTotal = 15;
         simpleFactory.setEvenValid(false);     // Every other validation fails
         simpleFactory.setDestroyLatency(100);  // Destroy takes 100 ms
         simpleFactory.setMaxTotal(maxTotal); // (makes - destroys) bound
         simpleFactory.setValidationEnabled(true);
         genericObjectPool.setMaxTotal(maxTotal);
         genericObjectPool.setMaxIdle(-1);
         genericObjectPool.setTestOnReturn(true);
         genericObjectPool.setMaxWaitMillis(1000L);
         runTestThreads(5, 10, 50, genericObjectPool);
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     @SuppressWarnings("rawtypes")
     public void testMaxTotalUnderLoad() {
         // Config
         final int numThreads = 199; // And main thread makes a round 200.
         final int numIter = 20;
         final int delay = 25;
         final int maxTotal = 10;
 
         simpleFactory.setMaxTotal(maxTotal);
         genericObjectPool.setMaxTotal(maxTotal);
         genericObjectPool.setBlockWhenExhausted(true);
         genericObjectPool.setTimeBetweenEvictionRuns(Duration.ofMillis(-1));
 
         // Start threads to borrow objects
         final TestThread[] threads = new TestThread[numThreads];
         for(int i=0;i<numThreads;i++) {
             // Factor of 2 on iterations so main thread does work whilst other
             // threads are running. Factor of 2 on delay so average delay for
             // other threads == actual delay for main thread
             threads[i] = new TestThread<>(genericObjectPool, numIter * 2, delay * 2);
             final Thread t = new Thread(threads[i]);
             t.start();
         }
         // Give the threads a chance to start doing some work
         Waiter.sleepQuietly(5000);
 
         for (int i = 0; i < numIter; i++) {
             String obj = null;
             try {
                 Waiter.sleepQuietly(delay);
                 obj = genericObjectPool.borrowObject();
                 // Under load, observed numActive > maxTotal
                 if (genericObjectPool.getNumActive() > genericObjectPool.getMaxTotal()) {
                     throw new IllegalStateException("Too many active objects");
                 }
                 Waiter.sleepQuietly(delay);
             } catch (final Exception e) {
                 // Shouldn't happen
                 e.printStackTrace();
                 fail("Exception on borrow");
             } finally {
                 if (obj != null) {
                     try {
                         genericObjectPool.returnObject(obj);
                     } catch (final Exception e) {
                         // Ignore
                     }
                 }
             }
         }
 
         for (int i = 0; i < numThreads; i++) {
             while(!threads[i].complete()) {
                 Waiter.sleepQuietly(500L);
             }
             if(threads[i].failed()) {
                 fail("Thread " + i + " failed: " + threads[i].error.toString());
             }
         }
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testMaxTotalZero() throws Exception {
         genericObjectPool.setMaxTotal(0);
         genericObjectPool.setBlockWhenExhausted(false);
         assertThrows(NoSuchElementException.class, () -> genericObjectPool.borrowObject());
     }
 
     /*
      * Test multi-threaded pool access.
      * Multiple threads, but maxTotal only allows half the threads to succeed.
      *
      * This test was prompted by Continuum build failures in the Commons DBCP test case:
      * TestPerUserPoolDataSource.testMultipleThreads2()
      * Let's see if the this fails on Continuum too!
      */
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testMaxWaitMultiThreaded() throws Exception {
         final long maxWait = 500; // wait for connection
         final long holdTime = 2 * maxWait; // how long to hold connection
         final int threads = 10; // number of threads to grab the object initially
         genericObjectPool.setBlockWhenExhausted(true);
         genericObjectPool.setMaxWaitMillis(maxWait);
         genericObjectPool.setMaxTotal(threads);
         // Create enough threads so half the threads will have to wait
         final WaitingTestThread[] wtt = new WaitingTestThread[threads * 2];
         for (int i = 0; i < wtt.length; i++) {
             wtt[i] = new WaitingTestThread(genericObjectPool, holdTime);
         }
         final long originMillis = System.currentTimeMillis() - 1000;
         for (final WaitingTestThread element : wtt) {
             element.start();
         }
         int failed = 0;
         for (final WaitingTestThread element : wtt) {
             element.join();
             if (element.thrown != null){
                 failed++;
             }
         }
         if (DISPLAY_THREAD_DETAILS || wtt.length/2 != failed){
             System.out.println(
                     "MaxWait: " + maxWait +
                     " HoldTime: " + holdTime +
                      " MaxTotal: " + threads +
                     " Threads: " + wtt.length +
                     " Failed: " + failed
                     );
             for (final WaitingTestThread wt : wtt) {
                 System.out.println(
                         "PreBorrow: " + (wt.preBorrowMillis - originMillis) +
                         " PostBorrow: " + (wt.postBorrowMillis != 0 ? wt.postBorrowMillis - originMillis : -1) +
                         " BorrowTime: " + (wt.postBorrowMillis != 0 ? wt.postBorrowMillis - wt.preBorrowMillis : -1) +
                         " PostReturn: " + (wt.postReturnMillis != 0 ? wt.postReturnMillis - originMillis : -1) +
                         " Ended: " + (wt.endedMillis - originMillis) +
                         " ObjId: " + wt.objectId
                         );
             }
         }
         assertEquals(wtt.length / 2, failed, "Expected half the threads to fail");
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testMinIdle() throws Exception {
         genericObjectPool.setMaxIdle(500);
         genericObjectPool.setMinIdle(5);
         genericObjectPool.setMaxTotal(10);
         genericObjectPool.setNumTestsPerEvictionRun(0);
         genericObjectPool.setMinEvictableIdleTime(Duration.ofMillis(50));
         genericObjectPool.setTimeBetweenEvictionRuns(Duration.ofMillis(100));
         genericObjectPool.setTestWhileIdle(true);
 
         Waiter.sleepQuietly(150L);
         assertEquals(5, genericObjectPool.getNumIdle(), "Should be 5 idle, found " + genericObjectPool.getNumIdle());
 
         final String[] active = new String[5];
         active[0] = genericObjectPool.borrowObject();
 
         Waiter.sleepQuietly(150L);
         assertEquals(5, genericObjectPool.getNumIdle(), "Should be 5 idle, found " + genericObjectPool.getNumIdle());
 
         for (int i = 1; i < 5; i++) {
             active[i] = genericObjectPool.borrowObject();
         }
 
         Waiter.sleepQuietly(150L);
         assertEquals(5, genericObjectPool.getNumIdle(), "Should be 5 idle, found " + genericObjectPool.getNumIdle());
 
         for (int i = 0; i < 5; i++) {
             genericObjectPool.returnObject(active[i]);
         }
 
         Waiter.sleepQuietly(150L);
         assertEquals(10, genericObjectPool.getNumIdle(), "Should be 10 idle, found " + genericObjectPool.getNumIdle());
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testMinIdleMaxTotal() throws Exception {
         genericObjectPool.setMaxIdle(500);
         genericObjectPool.setMinIdle(5);
         genericObjectPool.setMaxTotal(10);
         genericObjectPool.setNumTestsPerEvictionRun(0);
         genericObjectPool.setMinEvictableIdleTime(Duration.ofMillis(50));
         genericObjectPool.setTimeBetweenEvictionRuns(Duration.ofMillis(100));
         genericObjectPool.setTestWhileIdle(true);
 
         Waiter.sleepQuietly(150L);
         assertEquals(5, genericObjectPool.getNumIdle(), "Should be 5 idle, found " + genericObjectPool.getNumIdle());
 
         final String[] active = new String[10];
 
         Waiter.sleepQuietly(150L);
         assertEquals(5, genericObjectPool.getNumIdle(), "Should be 5 idle, found " + genericObjectPool.getNumIdle());
 
         for (int i = 0; i < 5; i++) {
             active[i] = genericObjectPool.borrowObject();
         }
 
         Waiter.sleepQuietly(150L);
         assertEquals(5, genericObjectPool.getNumIdle(), "Should be 5 idle, found " + genericObjectPool.getNumIdle());
 
         for(int i = 0 ; i < 5 ; i++) {
             genericObjectPool.returnObject(active[i]);
         }
 
         Waiter.sleepQuietly(150L);
         assertEquals(10, genericObjectPool.getNumIdle(), "Should be 10 idle, found " + genericObjectPool.getNumIdle());
 
         for (int i = 0; i < 10; i++) {
             active[i] = genericObjectPool.borrowObject();
         }
 
         Waiter.sleepQuietly(150L);
         assertEquals(0, genericObjectPool.getNumIdle(), "Should be 0 idle, found " + genericObjectPool.getNumIdle());
 
         for (int i = 0; i < 10; i++) {
             genericObjectPool.returnObject(active[i]);
         }
 
         Waiter.sleepQuietly(150L);
         assertEquals(10, genericObjectPool.getNumIdle(), "Should be 10 idle, found " + genericObjectPool.getNumIdle());
     }
 
     /**
      * Verifies that returning an object twice (without borrow in between) causes ISE
      * but does not re-validate or re-passivate the instance.
      *
      * JIRA: POOL-285
      */
     @Test
     public void testMultipleReturn() throws Exception {
         final WaiterFactory<String> factory = new WaiterFactory<>(0, 0, 0, 0, 0, 0);
         try (final GenericObjectPool<Waiter> pool = new GenericObjectPool<>(factory)) {
             pool.setTestOnReturn(true);
             final Waiter waiter = pool.borrowObject();
             pool.returnObject(waiter);
             assertEquals(1, waiter.getValidationCount());
             assertEquals(1, waiter.getPassivationCount());
             try {
                 pool.returnObject(waiter);
                 fail("Expecting IllegalStateException from multiple return");
             } catch (final IllegalStateException ex) {
                 // Exception is expected, now check no repeat validation/passivation
                 assertEquals(1, waiter.getValidationCount());
                 assertEquals(1, waiter.getPassivationCount());
             }
         }
     }
 
     // POOL-248
     @Test
     public void testMultipleReturnOfSameObject() throws Exception {
         try (final GenericObjectPool<String> pool = new GenericObjectPool<>(simpleFactory, new GenericObjectPoolConfig<>())) {
 
             assertEquals(0, pool.getNumActive());
             assertEquals(0, pool.getNumIdle());
 
             final String obj = pool.borrowObject();
 
             assertEquals(1, pool.getNumActive());
             assertEquals(0, pool.getNumIdle());
 
             pool.returnObject(obj);
 
             assertEquals(0, pool.getNumActive());
             assertEquals(1, pool.getNumIdle());
 
             assertThrows(IllegalStateException.class,
                     () -> pool.returnObject(obj));
 
             assertEquals(0, pool.getNumActive());
             assertEquals(1, pool.getNumIdle());
         }
     }
 
     /**
      * Verifies that when a borrowed object is mutated in a way that does not
      * preserve equality and hash code, the pool can recognized it on return.
      *
      * JIRA: POOL-284
      */
     @Test
     public void testMutable() throws Exception {
         final HashSetFactory factory = new HashSetFactory();
         try (final GenericObjectPool<HashSet<String>> pool = new GenericObjectPool<>(factory,
                 new GenericObjectPoolConfig<>())) {
             final HashSet<String> s1 = pool.borrowObject();
             final HashSet<String> s2 = pool.borrowObject();
             s1.add("One");
             s2.add("One");
             pool.returnObject(s1);
             pool.returnObject(s2);
         }
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testNegativeMaxTotal() throws Exception {
         genericObjectPool.setMaxTotal(-1);
         genericObjectPool.setBlockWhenExhausted(false);
         final String obj = genericObjectPool.borrowObject();
         assertEquals(getNthObject(0), obj);
         genericObjectPool.returnObject(obj);
     }
 
     /**
      * Verifies that concurrent threads never "share" instances
      */
     @Test
     public void testNoInstanceOverlap() {
         final int maxTotal = 5;
         final int numThreads = 100;
         final int delay = 1;
         final int iterations = 1000;
         final AtomicIntegerFactory factory = new AtomicIntegerFactory();
         try (final GenericObjectPool<AtomicInteger> pool = new GenericObjectPool<>(factory)) {
             pool.setMaxTotal(maxTotal);
             pool.setMaxIdle(maxTotal);
             pool.setTestOnBorrow(true);
             pool.setBlockWhenExhausted(true);
             pool.setMaxWaitMillis(-1);
             runTestThreads(numThreads, iterations, delay, pool);
             assertEquals(0, pool.getDestroyedByBorrowValidationCount());
         }
     }
 
     /**
      * POOL-376
      */
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testNoInvalidateNPE() throws Exception {
         genericObjectPool.setMaxTotal(1);
         genericObjectPool.setTestOnCreate(true);
         genericObjectPool.setMaxWaitMillis(-1);
         final String obj = genericObjectPool.borrowObject();
         // Make validation fail - this will cause create() to return null
         simpleFactory.setValid(false);
         // Create a take waiter
         final WaitingTestThread wtt = new WaitingTestThread(genericObjectPool, 200);
         wtt.start();
         // Give wtt time to start
         Thread.sleep(200);
         genericObjectPool.invalidateObject(obj);
         // Now allow create to succeed so waiter can be served
         simpleFactory.setValid(true);
     }
 
     /**
      * Verify that when a factory returns a null object, pool methods throw NPE.
      * @throws InterruptedException
      */
     @Test
     @Timeout(value = 1000, unit = TimeUnit.MILLISECONDS)
     public void testNPEOnFactoryNull() throws Exception {
         final DisconnectingWaiterFactory<String> factory = new DisconnectingWaiterFactory<>(
             () -> null,  // Override default to always return null from makeObject
             DisconnectingWaiterFactory.DEFAULT_DISCONNECTED_LIFECYCLE_ACTION,
             DisconnectingWaiterFactory.DEFAULT_DISCONNECTED_VALIDATION_ACTION
         );
         final GenericObjectPool<Waiter> pool = new GenericObjectPool<>(factory);
         pool.setTestOnBorrow(true);
         pool.setMaxTotal(-1);
         pool.setMinIdle(1);
         // Disconnect the factory - will always return null in this state
         factory.disconnect();
         try {
             pool.borrowObject();
             fail("Expecting NullPointerException");
         } catch (final NullPointerException ex) {
             // expected
         }
         try {
             pool.addObject();
             fail("Expecting NullPointerException");
         } catch (final NullPointerException ex2) {
             // expected
         }
         try {
             pool.ensureMinIdle();
             fail("Expecting NullPointerException");
         } catch (final NullPointerException ex3) {
             // expected
         }
         pool.close();
     }
 
     @Test
     public void testPreparePool() throws Exception {
         genericObjectPool.setMinIdle(1);
         genericObjectPool.setMaxTotal(1);
         genericObjectPool.preparePool();
         assertEquals(1, genericObjectPool.getNumIdle());
         final String obj = genericObjectPool.borrowObject();
         genericObjectPool.preparePool();
         assertEquals(0, genericObjectPool.getNumIdle());
         genericObjectPool.setMinIdle(0);
         genericObjectPool.returnObject(obj);
         genericObjectPool.preparePool();
         assertEquals(1, genericObjectPool.getNumIdle());
     }
 
     @Test/* maxWaitMillis x2 + padding */
     @Timeout(value = 1200, unit = TimeUnit.MILLISECONDS)
     public void testReturnBorrowObjectWithingMaxWaitDuration() throws Exception {
         final Duration maxWaitDuration = Duration.ofMillis(500);
         try (final GenericObjectPool<String> createSlowObjectFactoryPool = new GenericObjectPool<>(createSlowObjectFactory(Duration.ofSeconds(60)))) {
             createSlowObjectFactoryPool.setMaxTotal(1);
             createSlowObjectFactoryPool.setMaxWait(maxWaitDuration);
             // thread1 tries creating a slow object to make pool full.
             final WaitingTestThread thread1 = new WaitingTestThread(createSlowObjectFactoryPool, 0);
             thread1.start();
             // Wait for thread1's reaching to create().
             Thread.sleep(100);
             // another one tries borrowObject. It should return within maxWaitMillis.
             assertThrows(NoSuchElementException.class, () -> createSlowObjectFactoryPool.borrowObject(maxWaitDuration),
                     "borrowObject must fail due to timeout by maxWait");
             assertTrue(thread1.isAlive());
         }
     }
 
     @Test/* maxWaitMillis x2 + padding */
     @Timeout(value = 1200, unit = TimeUnit.MILLISECONDS)
     public void testReturnBorrowObjectWithingMaxWaitMillis() throws Exception {
         final long maxWaitMillis = 500;
         try (final GenericObjectPool<String> createSlowObjectFactoryPool = new GenericObjectPool<>(createSlowObjectFactory(Duration.ofSeconds(60)))) {
             createSlowObjectFactoryPool.setMaxTotal(1);
             createSlowObjectFactoryPool.setMaxWaitMillis(maxWaitMillis);
             // thread1 tries creating a slow object to make pool full.
             final WaitingTestThread thread1 = new WaitingTestThread(createSlowObjectFactoryPool, 0);
             thread1.start();
             // Wait for thread1's reaching to create().
             Thread.sleep(100);
             // another one tries borrowObject. It should return within maxWaitMillis.
             assertThrows(NoSuchElementException.class, () -> createSlowObjectFactoryPool.borrowObject(maxWaitMillis),
                     "borrowObject must fail due to timeout by maxWait");
             assertTrue(thread1.isAlive());
         }
     }
 
     /**
      * This is the test case for POOL-263. It is disabled since it will always
      * pass without artificial delay being injected into GOP.returnObject() and
      * a way to this hasn't currently been found that doesn't involve
      * polluting the GOP implementation. The artificial delay needs to be
      * inserted just before the final call to isLifo() in the returnObject()
      * method.
      */
     //@Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testReturnObject() throws Exception {
 
         genericObjectPool.setMaxTotal(1);
         genericObjectPool.setMaxIdle(-1);
         final String active = genericObjectPool.borrowObject();
 
         assertEquals(1, genericObjectPool.getNumActive());
         assertEquals(0, genericObjectPool.getNumIdle());
 
         final Thread t = new Thread(() -> genericObjectPool.close());
         t.start();
 
         genericObjectPool.returnObject(active);
 
         // Wait for the close() thread to complete
         while (t.isAlive()) {
             Thread.sleep(50);
         }
 
         assertEquals(0, genericObjectPool.getNumIdle());
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testSetConfig() throws Exception {
         final GenericObjectPoolConfig<String> expected = new GenericObjectPoolConfig<>();
         assertConfiguration(expected, genericObjectPool);
         expected.setMaxTotal(2);
         expected.setMaxIdle(3);
         expected.setMaxWait(Duration.ofMillis(5));
         expected.setMinEvictableIdleDuration(Duration.ofMillis(7L));
         expected.setNumTestsPerEvictionRun(9);
         expected.setTestOnCreate(true);
         expected.setTestOnBorrow(true);
         expected.setTestOnReturn(true);
         expected.setTestWhileIdle(true);
         expected.setTimeBetweenEvictionRuns(Duration.ofMillis(11L));
         expected.setBlockWhenExhausted(false);
         genericObjectPool.setConfig(expected);
         assertConfiguration(expected, genericObjectPool);
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testSettersAndGetters() throws Exception {
         {
             // The object receives an Exception during its creation to prevent
             // memory leaks. See BaseGenericObjectPool constructor for more details.
             assertNotEquals("", genericObjectPool.getCreationStackTrace());
         }
         {
             assertEquals(0, genericObjectPool.getBorrowedCount());
         }
         {
             assertEquals(0, genericObjectPool.getReturnedCount());
         }
         {
             assertEquals(0, genericObjectPool.getCreatedCount());
         }
         {
             assertEquals(0, genericObjectPool.getDestroyedCount());
         }
         {
             assertEquals(0, genericObjectPool.getDestroyedByEvictorCount());
         }
         {
             assertEquals(0, genericObjectPool.getDestroyedByBorrowValidationCount());
         }
         {
             assertEquals(0, genericObjectPool.getMeanActiveTimeMillis());
         }
         {
             assertEquals(0, genericObjectPool.getMeanIdleTimeMillis());
         }
         {
             assertEquals(0, genericObjectPool.getMeanBorrowWaitTimeMillis());
         }
         {
             assertEquals(0, genericObjectPool.getMaxBorrowWaitTimeMillis());
         }
         {
             assertEquals(0, genericObjectPool.getNumIdle());
         }
         {
             genericObjectPool.setMaxTotal(123);
             assertEquals(123, genericObjectPool.getMaxTotal());
         }
         {
             genericObjectPool.setMaxIdle(12);
             assertEquals(12, genericObjectPool.getMaxIdle());
         }
         {
             genericObjectPool.setMaxWaitMillis(1234L);
             assertEquals(1234L, genericObjectPool.getMaxWaitMillis());
         }
         {
             genericObjectPool.setMinEvictableIdleTimeMillis(12345L);
             assertEquals(12345L, genericObjectPool.getMinEvictableIdleDuration().toMillis());
             assertEquals(12345L, genericObjectPool.getMinEvictableIdleTimeMillis());
             assertEquals(12345L, genericObjectPool.getMinEvictableIdleTime().toMillis());
         }
         {
             genericObjectPool.setNumTestsPerEvictionRun(11);
             assertEquals(11, genericObjectPool.getNumTestsPerEvictionRun());
         }
         {
             genericObjectPool.setTestOnBorrow(true);
             assertTrue(genericObjectPool.getTestOnBorrow());
             genericObjectPool.setTestOnBorrow(false);
             assertFalse(genericObjectPool.getTestOnBorrow());
         }
         {
             genericObjectPool.setTestOnReturn(true);
             assertTrue(genericObjectPool.getTestOnReturn());
             genericObjectPool.setTestOnReturn(false);
             assertFalse(genericObjectPool.getTestOnReturn());
         }
         {
             genericObjectPool.setTestWhileIdle(true);
             assertTrue(genericObjectPool.getTestWhileIdle());
             genericObjectPool.setTestWhileIdle(false);
             assertFalse(genericObjectPool.getTestWhileIdle());
         }
         {
             genericObjectPool.setTimeBetweenEvictionRunsMillis(11235L);
             assertEquals(11235L, genericObjectPool.getDurationBetweenEvictionRuns().toMillis());
             assertEquals(11235L, genericObjectPool.getTimeBetweenEvictionRunsMillis());
             assertEquals(11235L, genericObjectPool.getTimeBetweenEvictionRuns().toMillis());
         }
         {
             genericObjectPool.setSoftMinEvictableIdleTimeMillis(12135L);
             assertEquals(12135L, genericObjectPool.getSoftMinEvictableIdleDuration().toMillis());
             assertEquals(12135L, genericObjectPool.getSoftMinEvictableIdleTimeMillis());
             assertEquals(12135L, genericObjectPool.getSoftMinEvictableIdleTime().toMillis());
         }
         {
             genericObjectPool.setBlockWhenExhausted(true);
             assertTrue(genericObjectPool.getBlockWhenExhausted());
             genericObjectPool.setBlockWhenExhausted(false);
             assertFalse(genericObjectPool.getBlockWhenExhausted());
         }
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testStartAndStopEvictor() throws Exception {
         // set up pool without evictor
         genericObjectPool.setMaxIdle(6);
         genericObjectPool.setMaxTotal(6);
         genericObjectPool.setNumTestsPerEvictionRun(6);
         genericObjectPool.setMinEvictableIdleTime(Duration.ofMillis(100));
 
         for (int j = 0; j < 2; j++) {
             // populate the pool
             {
                 final String[] active = new String[6];
                 for (int i = 0; i < 6; i++) {
                     active[i] = genericObjectPool.borrowObject();
                 }
                 for (int i = 0; i < 6; i++) {
                     genericObjectPool.returnObject(active[i]);
                 }
             }
 
             // note that it stays populated
             assertEquals(6, genericObjectPool.getNumIdle(), "Should have 6 idle");
 
             // start the evictor
             genericObjectPool.setTimeBetweenEvictionRuns(Duration.ofMillis(50));
 
             // wait a second (well, .2 seconds)
             Waiter.sleepQuietly(200L);
 
             // assert that the evictor has cleared out the pool
             assertEquals(0, genericObjectPool.getNumIdle(), "Should have 0 idle");
 
             // stop the evictor
             genericObjectPool.startEvictor(Duration.ZERO);
         }
     }
 
     @Test
     public void testSwallowedExceptionListener() {
         genericObjectPool.setSwallowedExceptionListener(null); // must simply return
         final List<Exception> swallowedExceptions = new ArrayList<>();
         /*
          * A simple listener, that will throw a OOM on 3rd exception.
          */
         final SwallowedExceptionListener listener = e -> {
             if (swallowedExceptions.size() == 2) {
                 throw new OutOfMemoryError();
             }
             swallowedExceptions.add(e);
         };
         genericObjectPool.setSwallowedExceptionListener(listener);
 
         final Exception e1 = new Exception();
         final Exception e2 = new ArrayIndexOutOfBoundsException();
 
         genericObjectPool.swallowException(e1);
         genericObjectPool.swallowException(e2);
 
         assertThrows(OutOfMemoryError.class, () -> genericObjectPool.swallowException(e1));
 
         assertEquals(2, swallowedExceptions.size());
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testThreaded1() throws Exception {
         genericObjectPool.setMaxTotal(15);
         genericObjectPool.setMaxIdle(15);
         genericObjectPool.setMaxWaitMillis(1000L);
         runTestThreads(20, 100, 50, genericObjectPool);
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testTimeoutNoLeak() throws Exception {
         genericObjectPool.setMaxTotal(2);
         genericObjectPool.setMaxWaitMillis(10);
         genericObjectPool.setBlockWhenExhausted(true);
         final String obj = genericObjectPool.borrowObject();
         final String obj2 = genericObjectPool.borrowObject();
         assertThrows(NoSuchElementException.class, () -> genericObjectPool.borrowObject());
         genericObjectPool.returnObject(obj2);
         genericObjectPool.returnObject(obj);
 
         genericObjectPool.borrowObject();
         genericObjectPool.borrowObject();
     }
 
     /**
      * Tests POOL-361
      */
     @Test
     public void testValidateOnCreate() throws Exception {
         genericObjectPool.setTestOnCreate(true);
         genericObjectPool.addObject();
         assertEquals(1, simpleFactory.validateCounter);
     }
 
     /**
      * Tests POOL-361
      */
     @Test
     public void testValidateOnCreateFailure() throws Exception {
         genericObjectPool.setTestOnCreate(true);
         genericObjectPool.setTestOnBorrow(false);
         genericObjectPool.setMaxTotal(2);
         simpleFactory.setValid(false);
         // Make sure failed validations do not leak capacity
         genericObjectPool.addObject();
         genericObjectPool.addObject();
         assertEquals(0, genericObjectPool.getNumIdle());
         assertEquals(0, genericObjectPool.getNumActive());
         simpleFactory.setValid(true);
         final String obj = genericObjectPool.borrowObject();
         assertNotNull(obj);
         genericObjectPool.addObject();
         // Should have one idle, one out now
         assertEquals(1, genericObjectPool.getNumIdle());
         assertEquals(1, genericObjectPool.getNumActive());
 	}
 
     /**
      * Verify that threads waiting on a depleted pool get served when a returning object fails
      * validation.
      *
      * JIRA: POOL-240
      *
      * @throws Exception May occur in some failure modes
      */
     @Test
     public void testValidationFailureOnReturnFreesCapacity() throws Exception {
         final SimpleFactory factory = new SimpleFactory();
         factory.setValid(false); // Validate will always fail
         factory.setValidationEnabled(true);
         try (final GenericObjectPool<String> pool = new GenericObjectPool<>(factory)) {
             pool.setMaxTotal(2);
             pool.setMaxWaitMillis(1500);
             pool.setTestOnReturn(true);
             pool.setTestOnBorrow(false);
             // Borrow an instance and hold if for 5 seconds
             final WaitingTestThread thread1 = new WaitingTestThread(pool, 5000);
             thread1.start();
             // Borrow another instance and return it after 500 ms (validation will fail)
             final WaitingTestThread thread2 = new WaitingTestThread(pool, 500);
             thread2.start();
             Thread.sleep(50);
             // Try to borrow an object
             final String obj = pool.borrowObject();
             pool.returnObject(obj);
         }
     }
 
     // POOL-276
     @Test
     public void testValidationOnCreateOnly() throws Exception {
         genericObjectPool.setMaxTotal(1);
         genericObjectPool.setTestOnCreate(true);
         genericObjectPool.setTestOnBorrow(false);
         genericObjectPool.setTestOnReturn(false);
         genericObjectPool.setTestWhileIdle(false);
 
         final String o1 = genericObjectPool.borrowObject();
         assertEquals("0", o1);
         final Timer t = new Timer();
         t.schedule(
                 new TimerTask() {
                     @Override
                     public void run() {
                         genericObjectPool.returnObject(o1);
                     }
                 }, 3000);
 
         final String o2 = genericObjectPool.borrowObject();
         assertEquals("0", o2);
 
         assertEquals(1, simpleFactory.validateCounter);
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testWhenExhaustedBlock() throws Exception {
         genericObjectPool.setMaxTotal(1);
         genericObjectPool.setBlockWhenExhausted(true);
         genericObjectPool.setMaxWaitMillis(10L);
         final String obj1 = genericObjectPool.borrowObject();
         assertNotNull(obj1);
         assertThrows(NoSuchElementException.class, () -> genericObjectPool.borrowObject());
         genericObjectPool.returnObject(obj1);
         genericObjectPool.close();
     }
 
     /**
      * POOL-189
      *
      * @throws Exception May occur in some failure modes
      */
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testWhenExhaustedBlockClosePool() throws Exception {
         genericObjectPool.setMaxTotal(1);
         genericObjectPool.setBlockWhenExhausted(true);
         genericObjectPool.setMaxWaitMillis(-1);
         final Object obj1 = genericObjectPool.borrowObject();
 
         // Make sure an object was obtained
         assertNotNull(obj1);
 
         // Create a separate thread to try and borrow another object
         final WaitingTestThread wtt = new WaitingTestThread(genericObjectPool, 200);
         wtt.start();
         // Give wtt time to start
         Thread.sleep(200);
 
         // close the pool (Bug POOL-189)
         genericObjectPool.close();
 
         // Give interrupt time to take effect
         Thread.sleep(200);
 
         // Check thread was interrupted
         assertTrue(wtt.thrown instanceof InterruptedException);
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testWhenExhaustedBlockInterrupt() throws Exception {
         genericObjectPool.setMaxTotal(1);
         genericObjectPool.setBlockWhenExhausted(true);
         genericObjectPool.setMaxWaitMillis(-1);
         final String obj1 = genericObjectPool.borrowObject();
 
         // Make sure on object was obtained
         assertNotNull(obj1);
 
         // Create a separate thread to try and borrow another object
         final WaitingTestThread wtt = new WaitingTestThread(genericObjectPool, 200000);
         wtt.start();
         // Give wtt time to start
         Thread.sleep(200);
         wtt.interrupt();
 
         // Give interrupt time to take effect
         Thread.sleep(200);
 
         // Check thread was interrupted
         assertTrue(wtt.thrown instanceof InterruptedException);
 
         // Return object to the pool
         genericObjectPool.returnObject(obj1);
 
         // Bug POOL-162 - check there is now an object in the pool
         genericObjectPool.setMaxWaitMillis(10L);
         String obj2 = null;
         try {
             obj2 = genericObjectPool.borrowObject();
             assertNotNull(obj2);
         } catch (final NoSuchElementException e) {
             // Not expected
             fail("NoSuchElementException not expected");
         }
         genericObjectPool.returnObject(obj2);
         genericObjectPool.close();
 
     }
 
     @Test
     @Timeout(value = 60000, unit = TimeUnit.MILLISECONDS)
     public void testWhenExhaustedFail() throws Exception {
         genericObjectPool.setMaxTotal(1);
         genericObjectPool.setBlockWhenExhausted(false);
         final String obj1 = genericObjectPool.borrowObject();
         assertNotNull(obj1);
         assertThrows(NoSuchElementException.class, () -> genericObjectPool.borrowObject());
         genericObjectPool.returnObject(obj1);
         assertEquals(1, genericObjectPool.getNumIdle());
         genericObjectPool.close();
     }
 
 }