org.apache.commons.lang
Class ObjectUtils.Null

java.lang.Object
  org.apache.commons.lang.ObjectUtils.Null

All Implemented Interfaces:

java.io.Serializable

Enclosing class:

ObjectUtils

public static class ObjectUtils.Null

extends java.lang.Object

implements java.io.Serializable

Class used as a null placeholder where null has another meaning.

For example, in a HashMap the HashMap.get(java.lang.Object) method returns null if the Map contains null or if there is no matching key. The Null placeholder can be used to distinguish between these two cases.

Another example is Hashtable, where null cannot be stored.

See Also:

Serialized Form

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait