Email.java

/*
 * 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.mail2.javax;

import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Properties;

import javax.mail.Authenticator;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import javax.mail.internet.MimeUtility;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;

import org.apache.commons.mail2.core.EmailConstants;
import org.apache.commons.mail2.core.EmailException;
import org.apache.commons.mail2.core.EmailUtils;
import org.apache.commons.mail2.javax.util.IDNEmailAddressConverter;

/**
 * The abstract class for all email messages. This class sets the sender's email, name, receiver's email, name, subject, and send date.
 * <p>
 * Subclasses are responsible for setting the message body.
 * </p>
 *
 * @since 1.0
 */
public abstract class Email {

    /**
     * Empty array.
     */
    private static final InternetAddress[] EMPTY_INTERNET_ADDRESS_ARRAY = {};

    /**
     * The email message to send.
     */
    private MimeMessage message;

    /**
     * The charset to use for this message.
     */
    private String charset;

    /**
     * The Address of the sending party, mandatory.
     */
    private InternetAddress fromAddress;

    /**
     * The Subject.
     */
    private String subject;

    /**
     * An attachment.
     */
    private MimeMultipart emailBody;

    /**
     * The content.
     */
    private Object content;

    /**
     * The content type.
     */
    private String contentType;

    /**
     * Set session debugging on or off.
     */
    private boolean debug;

    /**
     * Sent date.
     */
    private Date sentDate;

    /**
     * Instance of an {@code Authenticator} object that will be used when authentication is requested from the mail server.
     */
    private Authenticator authenticator;

    /**
     * The hostname of the mail server with which to connect. If null will try to get property from system.properties. If still null, quit.
     */
    private String hostName;

    /**
     * The port number of the mail server to connect to. Defaults to the standard port ( 25 ).
     */
    private String smtpPort = "25";

    /**
     * The port number of the SSL enabled SMTP server; defaults to the standard port, 465.
     */
    private String sslSmtpPort = "465";

    /**
     * List of "to" email addresses.
     */
    private List<InternetAddress> toList = new ArrayList<>();

    /**
     * List of "cc" email addresses.
     */
    private List<InternetAddress> ccList = new ArrayList<>();

    /**
     * List of "bcc" email addresses.
     */
    private List<InternetAddress> bccList = new ArrayList<>();

    /**
     * List of "replyTo" email addresses.
     */
    private List<InternetAddress> replyList = new ArrayList<>();

    /**
     * Address to which undeliverable mail should be sent. Because this is handled by JavaMail as a String property in the mail session, this property is of
     * type {@code String} rather than {@code InternetAddress}.
     */
    private String bounceAddress;

    /**
     * Used to specify the mail headers. Example:
     *
     * X-Mailer: Sendmail, X-Priority: 1( highest ) or 2( high ) 3( normal ) 4( low ) and 5( lowest ) Disposition-Notification-To: user@domain.net
     */
    private final Map<String, String> headers = new HashMap<>();

    /**
     * Whether to use POP3 before SMTP, and if so the settings.
     */
    private boolean popBeforeSmtp;

    /**
     * The host name of the POP3 server.
     */
    private String popHost;

    /**
     * The user name to log into the POP3 server.
     */
    private String popUsername;

    /**
     * The password to log into the POP3 server.
     */
    private String popPassword;

    /**
     * Does server require TLS encryption for authentication?
     */
    private boolean tls;

    /**
     * Does the current transport use SSL/TLS encryption upon connection?
     */
    private boolean ssl;

    /**
     * Socket I/O timeout value in milliseconds.
     */
    private int socketTimeout = Math.toIntExact(EmailConstants.SOCKET_TIMEOUT.toMillis());

    /**
     * Socket connection timeout value in milliseconds.
     */
    private int socketConnectionTimeout = Math.toIntExact(EmailConstants.SOCKET_TIMEOUT.toMillis());

    /**
     * If true, enables the use of the STARTTLS command (if supported by the server) to switch the connection to a TLS-protected connection before issuing any
     * login commands. Note that an appropriate trust store must configured so that the client will trust the server's certificate. Defaults to false.
     */
    private boolean startTlsEnabled;

    /**
     * If true, requires the use of the STARTTLS command. If the server doesn't support the STARTTLS command, or the command fails, the connect method will
     * fail. Defaults to false.
     */
    private boolean startTlsRequired;

    /**
     * Does the current transport use SSL/TLS encryption upon connection?
     */
    private boolean sslOnConnect;

    /**
     * If set to true, check the server identity as specified by RFC 2595. These additional checks based on the content of the server's certificate are intended
     * to prevent man-in-the-middle attacks. Defaults to false.
     */
    private boolean sslCheckServerIdentity;

    /**
     * If set to true, and a message has some valid and some invalid addresses, send the message anyway, reporting the partial failure with a
     * SendFailedException. If set to false (the default), the message is not sent to any of the recipients if there is an invalid recipient address. Defaults
     * to false.
     */
    private boolean sendPartial;

    /**
     * The Session to mail with.
     */
    private Session session;

    /**
     * Constructs a new instance.
     */
    public Email() {
        // empty
    }

    /**
     * Adds a blind BCC recipient to the email. The email address will also be used as the personal name. The name will be encoded by the charset of
     * {@link #setCharset(String)}. If it is not set, it will be encoded using the Java platform's default charset (UTF-16) if it contains non-ASCII characters;
     * otherwise, it is used as is.
     *
     * @param email A String.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address
     * @since 1.0
     */
    public Email addBcc(final String email) throws EmailException {
        return addBcc(email, null);
    }

    /**
     * Adds an array of blind BCC recipients to the email. The email addresses will also be used as the personal name. The names will be encoded by the charset
     * of {@link #setCharset(String)}. If it is not set, it will be encoded using the Java platform's default charset (UTF-16) if it contains non-ASCII
     * characters; otherwise, it is used as is.
     *
     * @param emails A String array.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address
     * @since 1.3
     */
    public Email addBcc(final String... emails) throws EmailException {
        EmailException.checkNonEmpty(emails, () -> "BCC list invalid.");
        for (final String email : emails) {
            addBcc(email, null);
        }
        return this;
    }

    /**
     * Adds a blind BCC recipient to the email using the specified address and the specified personal name. The name will be encoded by the charset of
     * {@link #setCharset(String)}. If it is not set, it will be encoded using the Java platform's default charset (UTF-16) if it contains non-ASCII characters;
     * otherwise, it is used as is.
     *
     * @param email A String.
     * @param name  A String.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address
     * @since 1.0
     */
    public Email addBcc(final String email, final String name) throws EmailException {
        return addBcc(email, name, charset);
    }

    /**
     * Adds a blind BCC recipient to the email using the specified address, personal name, and charset encoding for the name.
     *
     * @param email   A String.
     * @param name    A String.
     * @param charset The charset to encode the name with.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address
     * @since 1.1
     */
    public Email addBcc(final String email, final String name, final String charset) throws EmailException {
        bccList.add(createInternetAddress(email, name, charset));
        return this;
    }

    /**
     * Adds a recipient CC to the email. The email address will also be used as the personal name. The name will be encoded by the charset of
     * {@link #setCharset(String)}. If it is not set, it will be encoded using the Java platform's default charset (UTF-16) if it contains non-ASCII characters;
     * otherwise, it is used as is.
     *
     * @param email A String.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address.
     * @since 1.0
     */
    public Email addCc(final String email) throws EmailException {
        return addCc(email, null);
    }

    /**
     * Adds an array of CC recipients to the email. The email addresses will also be used as the personal name. The names will be encoded by the charset of
     * {@link #setCharset(String)}. If it is not set, it will be encoded using the Java platform's default charset (UTF-16) if it contains non-ASCII characters;
     * otherwise, it is used as is.
     *
     * @param emails A String array.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address.
     * @since 1.3
     */
    public Email addCc(final String... emails) throws EmailException {
        EmailException.checkNonEmpty(emails, () -> "CC list invalid.");
        for (final String email : emails) {
            addCc(email, null);
        }
        return this;
    }

    /**
     * Adds a recipient CC to the email using the specified address and the specified personal name. The name will be encoded by the charset of
     * {@link #setCharset(String)}. If it is not set, it will be encoded using the Java platform's default charset (UTF-16) if it contains non-ASCII characters;
     * otherwise, it is used as is.
     *
     * @param email A String.
     * @param name  A String.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address.
     * @since 1.0
     */
    public Email addCc(final String email, final String name) throws EmailException {
        return addCc(email, name, charset);
    }

    /**
     * Adds a recipient CC to the email using the specified address, personal name, and charset encoding for the name.
     *
     * @param email   A String.
     * @param name    A String.
     * @param charset The charset to encode the name with.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address or charset.
     * @since 1.1
     */
    public Email addCc(final String email, final String name, final String charset) throws EmailException {
        ccList.add(createInternetAddress(email, name, charset));
        return this;
    }

    /**
     * Adds a header ( name, value ) to the headers Map.
     *
     * @param name  A String with the name.
     * @param value A String with the value.
     * @since 1.0
     * @throws IllegalArgumentException if either {@code name} or {@code value} is null or empty
     */
    public void addHeader(final String name, final String value) {
        if (EmailUtils.isEmpty(name)) {
            throw new IllegalArgumentException("name can not be null or empty");
        }
        if (EmailUtils.isEmpty(value)) {
            throw new IllegalArgumentException("value can not be null or empty");
        }
        headers.put(name, value);
    }

    /**
     * Adds a reply to address to the email. The email address will also be used as the personal name. The name will be encoded by the charset of
     * {@link #setCharset(String)}. If it is not set, it will be encoded using the Java platform's default charset (UTF-16) if it contains non-ASCII characters;
     * otherwise, it is used as is.
     *
     * @param email A String.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address
     * @since 1.0
     */
    public Email addReplyTo(final String email) throws EmailException {
        return addReplyTo(email, null);
    }

    /**
     * Adds a reply to address to the email using the specified address and the specified personal name. The name will be encoded by the charset of
     * {@link #setCharset(String)}. If it is not set, it will be encoded using the Java platform's default charset (UTF-16) if it contains non-ASCII characters;
     * otherwise, it is used as is.
     *
     * @param email A String.
     * @param name  A String.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address
     * @since 1.0
     */
    public Email addReplyTo(final String email, final String name) throws EmailException {
        return addReplyTo(email, name, charset);
    }

    /**
     * Adds a reply to address to the email using the specified address, personal name, and charset encoding for the name.
     *
     * @param email   A String.
     * @param name    A String.
     * @param charset The charset to encode the name with.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address or charset.
     * @since 1.1
     */
    public Email addReplyTo(final String email, final String name, final String charset) throws EmailException {
        replyList.add(createInternetAddress(email, name, charset));
        return this;
    }

    /**
     * Adds a recipient TO to the email. The email address will also be used as the personal name. The name will be encoded by the charset of
     * {@link #setCharset(String)}. If it is not set, it will be encoded using the Java platform's default charset (UTF-16) if it contains non-ASCII characters;
     * otherwise, it is used as is.
     *
     * @param email A String.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address.
     * @since 1.0
     */
    public Email addTo(final String email) throws EmailException {
        return addTo(email, null);
    }

    /**
     * Adds a list of TO recipients to the email. The email addresses will also be used as the personal names. The names will be encoded by the charset of
     * {@link #setCharset(String)}. If it is not set, it will be encoded using the Java platform's default charset (UTF-16) if it contains non-ASCII characters;
     * otherwise, it is used as is.
     *
     * @param emails A String array.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address.
     * @since 1.3
     */
    public Email addTo(final String... emails) throws EmailException {
        EmailException.checkNonEmpty(emails, () -> "To list invalid.");
        for (final String email : emails) {
            addTo(email, null);
        }
        return this;
    }

    /**
     * Adds a recipient TO to the email using the specified address and the specified personal name. The name will be encoded by the charset of
     * {@link #setCharset(String)}. If it is not set, it will be encoded using the Java platform's default charset (UTF-16) if it contains non-ASCII characters;
     * otherwise, it is used as is.
     *
     * @param email A String.
     * @param name  A String.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address.
     * @since 1.0
     */
    public Email addTo(final String email, final String name) throws EmailException {
        return addTo(email, name, charset);
    }

    /**
     * Adds a recipient TO to the email using the specified address, personal name, and charset encoding for the name.
     *
     * @param email   A String.
     * @param name    A String.
     * @param charset The charset to encode the name with.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address or charset.
     * @since 1.1
     */
    public Email addTo(final String email, final String name, final String charset) throws EmailException {
        toList.add(createInternetAddress(email, name, charset));
        return this;
    }

    /**
     * Builds the MimeMessage. Please note that a user rarely calls this method directly and only if he/she is interested in the sending the underlying
     * MimeMessage without commons-email.
     *
     * @throws IllegalStateException if the MimeMessage was already built
     * @throws EmailException        if there was an error.
     * @since 1.0
     */
    public void buildMimeMessage() throws EmailException {
        if (message != null) {
            // [EMAIL-95] we assume that an email is not reused therefore invoking
            // buildMimeMessage() more than once is illegal.
            throw new IllegalStateException("The MimeMessage is already built.");
        }

        try {
            message = createMimeMessage(getMailSession());

            if (EmailUtils.isNotEmpty(subject)) {
                if (EmailUtils.isNotEmpty(charset)) {
                    message.setSubject(subject, charset);
                } else {
                    message.setSubject(subject);
                }
            }

            // update content type (and encoding)
            updateContentType(contentType);

            if (content != null) {
                if (EmailConstants.TEXT_PLAIN.equalsIgnoreCase(contentType) && content instanceof String) {
                    // EMAIL-104: call explicitly setText to use default mime charset
                    // (property "mail.mime.charset") in case none has been set
                    message.setText(content.toString(), charset);
                } else {
                    message.setContent(content, contentType);
                }
            } else if (emailBody != null) {
                if (contentType == null) {
                    message.setContent(emailBody);
                } else {
                    message.setContent(emailBody, contentType);
                }
            } else {
                message.setText("");
            }

            if (fromAddress != null) {
                message.setFrom(fromAddress);
            } else if (session.getProperty(EmailConstants.MAIL_SMTP_FROM) == null && session.getProperty(EmailConstants.MAIL_FROM) == null) {
                throw new EmailException("From address required");
            }

            if (toList.size() + ccList.size() + bccList.size() == 0) {
                throw new EmailException("At least one receiver address required");
            }

            if (!EmailUtils.isEmpty(toList)) {
                message.setRecipients(Message.RecipientType.TO, toInternetAddressArray(toList));
            }

            if (!EmailUtils.isEmpty(ccList)) {
                message.setRecipients(Message.RecipientType.CC, toInternetAddressArray(ccList));
            }

            if (!EmailUtils.isEmpty(bccList)) {
                message.setRecipients(Message.RecipientType.BCC, toInternetAddressArray(bccList));
            }

            if (!EmailUtils.isEmpty(replyList)) {
                message.setReplyTo(toInternetAddressArray(replyList));
            }

            if (!EmailUtils.isEmpty(headers)) {
                for (final Map.Entry<String, String> entry : headers.entrySet()) {
                    final String foldedValue = createFoldedHeaderValue(entry.getKey(), entry.getValue());
                    message.addHeader(entry.getKey(), foldedValue);
                }
            }

            if (message.getSentDate() == null) {
                message.setSentDate(getSentDate());
            }

            if (popBeforeSmtp) {
                // TODO Why is this not a Store leak? When to close?
                final Store store = session.getStore("pop3");
                store.connect(popHost, popUsername, popPassword);
            }
        } catch (final MessagingException e) {
            throw new EmailException(e);
        }
    }

    /**
     * When a mail session is already initialized setting the session properties has no effect. In order to flag the problem throw an IllegalStateException.
     *
     * @throws IllegalStateException when the mail session is already initialized
     */
    private void checkSessionAlreadyInitialized() {
        if (session != null) {
            throw new IllegalStateException("The mail session is already initialized");
        }
    }

    /**
     * Creates a folded header value containing 76 character chunks.
     *
     * @param name  the name of the header
     * @param value the value of the header
     * @return the folded header value
     * @throws IllegalArgumentException if either the name or value is null or empty
     */
    private String createFoldedHeaderValue(final String name, final String value) {
        if (EmailUtils.isEmpty(name)) {
            throw new IllegalArgumentException("name can not be null or empty");
        }
        if (EmailUtils.isEmpty(value)) {
            throw new IllegalArgumentException("value can not be null or empty");
        }
        try {
            return MimeUtility.fold(name.length() + 2, MimeUtility.encodeText(value, charset, null));
        } catch (final UnsupportedEncodingException e) {
            return value;
        }
    }

    /**
     * Creates an InternetAddress.
     *
     * @param email       An email address.
     * @param name        A name.
     * @param charsetName The name of the charset to encode the name with.
     * @return An internet address.
     * @throws EmailException Thrown when the supplied address, name or charset were invalid.
     */
    private InternetAddress createInternetAddress(final String email, final String name, final String charsetName) throws EmailException {
        try {
            final InternetAddress address = new InternetAddress(new IDNEmailAddressConverter().toASCII(email));
            // check name input
            if (EmailUtils.isNotEmpty(name)) {
                // check charset input.
                if (EmailUtils.isEmpty(charsetName)) {
                    address.setPersonal(name);
                } else {
                    // canonicalize the charset name and make sure
                    // the current platform supports it.
                    final Charset set = Charset.forName(charsetName);
                    address.setPersonal(name, set.name());
                }
            }
            // run sanity check on new InternetAddress object; if this fails
            // it will throw AddressException.
            address.validate();
            return address;
        } catch (final AddressException | UnsupportedEncodingException e) {
            throw new EmailException(e);
        }
    }

    /**
     * Creates a customized MimeMessage which can be implemented by a derived class, e.g. to set the message id.
     *
     * @param aSession mail session to be used
     * @return the newly created message
     */
    protected MimeMessage createMimeMessage(final Session aSession) {
        return new MimeMessage(aSession);
    }

    /**
     * Gets the authenticator.
     *
     * @return the authenticator.
     * @since 1.6.0
     */
    public Authenticator getAuthenticator() {
        return authenticator;
    }

    /**
     * Gets the list of "Bcc" addresses.
     *
     * @return List addresses
     */
    public List<InternetAddress> getBccAddresses() {
        return bccList;
    }

    /**
     * Gets the "bounce address" of this email.
     *
     * @return the bounce address as string
     * @since 1.4
     */
    public String getBounceAddress() {
        return bounceAddress;
    }

    /**
     * Gets the list of "CC" addresses.
     *
     * @return List addresses
     */
    public List<InternetAddress> getCcAddresses() {
        return ccList;
    }

    /**
     * Gets the Charset.
     *
     * @return the Charset.
     * @since 1.6.0
     */
    public String getCharsetName() {
        return charset;
    }

    /**
     * Gets the content.
     *
     * @return the content.
     * @since 1.6.0
     */
    public Object getContent() {
        return content;
    }

    /**
     * Gets the content type.
     *
     * @return the content type.
     * @since 1.6.0
     */
    public String getContentType() {
        return contentType;
    }

    /**
     * Gets the email body.
     *
     * @return the email body.
     * @since 1.6.0
     */
    public MimeMultipart getEmailBody() {
        return emailBody;
    }

    /**
     * Gets the sender of the email.
     *
     * @return from address
     */
    public InternetAddress getFromAddress() {
        return fromAddress;
    }

    /**
     * Gets the specified header.
     *
     * @param header A string with the header.
     * @return The value of the header, or null if no such header.
     * @since 1.5
     */
    public String getHeader(final String header) {
        return headers.get(header);
    }

    /**
     * Gets all headers on an Email.
     *
     * @return a Map of all headers.
     * @since 1.5
     */
    public Map<String, String> getHeaders() {
        return headers;
    }

    /**
     * Gets the host name of the SMTP server,
     *
     * @return host name
     */
    public String getHostName() {
        if (session != null) {
            return session.getProperty(EmailConstants.MAIL_HOST);
        }
        if (EmailUtils.isNotEmpty(hostName)) {
            return hostName;
        }
        return null;
    }

    /**
     * Gets the mail session used when sending this Email, creating the Session if necessary. When a mail session is already initialized setting the session
     * related properties will cause an IllegalStateException.
     *
     * @return A Session.
     * @throws EmailException if the host name was not set
     * @since 1.0
     */
    public Session getMailSession() throws EmailException {
        if (session == null) {
            final Properties properties = new Properties(System.getProperties());
            properties.setProperty(EmailConstants.MAIL_TRANSPORT_PROTOCOL, EmailConstants.SMTP);

            if (EmailUtils.isEmpty(hostName)) {
                hostName = properties.getProperty(EmailConstants.MAIL_HOST);
            }

            EmailException.checkNonEmpty(hostName, () -> "Cannot find valid hostname for mail session");

            properties.setProperty(EmailConstants.MAIL_PORT, smtpPort);
            properties.setProperty(EmailConstants.MAIL_HOST, hostName);
            properties.setProperty(EmailConstants.MAIL_DEBUG, String.valueOf(debug));

            properties.setProperty(EmailConstants.MAIL_TRANSPORT_STARTTLS_ENABLE, Boolean.toString(isStartTLSEnabled()));
            properties.setProperty(EmailConstants.MAIL_TRANSPORT_STARTTLS_REQUIRED, Boolean.toString(isStartTLSRequired()));

            properties.setProperty(EmailConstants.MAIL_SMTP_SEND_PARTIAL, Boolean.toString(isSendPartial()));
            properties.setProperty(EmailConstants.MAIL_SMTPS_SEND_PARTIAL, Boolean.toString(isSendPartial()));

            if (authenticator != null) {
                properties.setProperty(EmailConstants.MAIL_SMTP_AUTH, "true");
            }

            if (isSSLOnConnect()) {
                properties.setProperty(EmailConstants.MAIL_PORT, sslSmtpPort);
                properties.setProperty(EmailConstants.MAIL_SMTP_SOCKET_FACTORY_PORT, sslSmtpPort);
                properties.setProperty(EmailConstants.MAIL_SMTP_SOCKET_FACTORY_CLASS, "javax.net.ssl.SSLSocketFactory");
                properties.setProperty(EmailConstants.MAIL_SMTP_SOCKET_FACTORY_FALLBACK, "false");
            }

            if ((isSSLOnConnect() || isStartTLSEnabled()) && isSSLCheckServerIdentity()) {
                properties.setProperty(EmailConstants.MAIL_SMTP_SSL_CHECKSERVERIDENTITY, "true");
            }

            if (bounceAddress != null) {
                properties.setProperty(EmailConstants.MAIL_SMTP_FROM, bounceAddress);
            }

            if (socketTimeout > 0) {
                properties.setProperty(EmailConstants.MAIL_SMTP_TIMEOUT, Integer.toString(socketTimeout));
            }

            if (socketConnectionTimeout > 0) {
                properties.setProperty(EmailConstants.MAIL_SMTP_CONNECTIONTIMEOUT, Integer.toString(socketConnectionTimeout));
            }

            // changed this (back) to getInstance due to security exceptions
            // caused when testing using Maven
            session = Session.getInstance(properties, authenticator);
        }
        return session;
    }

    /**
     * Gets the message.
     *
     * @return the message.
     * @since 1.6.0
     */
    public MimeMessage getMessage() {
        return message;
    }

    /**
     * Gets the internal MimeMessage. Please note that the MimeMessage is built by the buildMimeMessage() method.
     *
     * @return the MimeMessage
     */
    public MimeMessage getMimeMessage() {
        return message;
    }

    /**
     * Gets the POP3 host.
     *
     * @return the POP3 host.
     * @since 1.6.0
     */
    public String getPopHost() {
        return popHost;
    }

    /**
     * Gets the POP3 password.
     *
     * @return the POP3 password.
     * @since 1.6.0
     */
    public String getPopPassword() {
        return popPassword;
    }

    /**
     * Gets the POP3 user name.
     *
     * @return the POP3 user name.
     * @since 1.6.0
     */
    public String getPopUserName() {
        return popUsername;
    }

    /**
     * Gets the list of "Reply-To" addresses.
     *
     * @return List addresses
     */
    public List<InternetAddress> getReplyToAddresses() {
        return replyList;
    }

    /**
     * Gets the sent date for the email.
     *
     * @return date to be used as the sent date for the email
     * @since 1.0
     */
    public Date getSentDate() {
        if (sentDate == null) {
            return new Date();
        }
        return new Date(sentDate.getTime());
    }

    /**
     * Gets the listening port of the SMTP server.
     *
     * @return SMTP port
     */
    public String getSmtpPort() {
        if (session != null) {
            return session.getProperty(EmailConstants.MAIL_PORT);
        }
        if (EmailUtils.isNotEmpty(smtpPort)) {
            return smtpPort;
        }
        return null;
    }

    /**
     * Gets the socket connection timeout value in milliseconds.
     *
     * @return the timeout in milliseconds.
     * @since 1.2
     */
    public int getSocketConnectionTimeout() {
        return socketConnectionTimeout;
    }

    /**
     * Gets the socket I/O timeout value in milliseconds.
     *
     * @return the socket I/O timeout
     * @since 1.2
     */
    public int getSocketTimeout() {
        return socketTimeout;
    }

    /**
     * Gets the current SSL port used by the SMTP transport.
     *
     * @return the current SSL port used by the SMTP transport
     */
    public String getSslSmtpPort() {
        if (session != null) {
            return session.getProperty(EmailConstants.MAIL_SMTP_SOCKET_FACTORY_PORT);
        }
        if (EmailUtils.isNotEmpty(sslSmtpPort)) {
            return sslSmtpPort;
        }
        return null;
    }

    /**
     * Gets the subject of the email.
     *
     * @return email subject
     */
    public String getSubject() {
        return subject;
    }

    /**
     * Gets the list of "To" addresses.
     *
     * @return List addresses
     */
    public List<InternetAddress> getToAddresses() {
        return toList;
    }

    /**
     * Tests whether debug is on.
     *
     * @return whether debug is on.
     * @since 1.6.0
     */
    public boolean isDebug() {
        return debug;
    }

    /**
     * Tests whether to use POP3 before SMTP, and if so the settings.
     *
     * @return whether to use POP3 before SMTP, and if so the settings.
     * @since 1.6.0
     */
    public boolean isPopBeforeSmtp() {
        return popBeforeSmtp;
    }

    /**
     * Tests whether partial sending of email is enabled.
     *
     * @return true if sending partial email is enabled.
     * @since 1.3.2
     */
    public boolean isSendPartial() {
        return sendPartial;
    }

    /**
     * Tests whether the server identity checked as specified by RFC 2595
     *
     * @return true if the server identity is checked.
     * @since 1.3
     */
    public boolean isSSLCheckServerIdentity() {
        return sslCheckServerIdentity;
    }

    /**
     * Tests whether SSL/TLS encryption for the transport is currently enabled (SMTPS/POPS).
     *
     * @return true if SSL enabled for the transport.
     * @since 1.3
     */
    public boolean isSSLOnConnect() {
        return sslOnConnect || ssl;
    }

    /**
     * Tests whether the client is configured to try to enable STARTTLS.
     *
     * @return true if using STARTTLS for authentication, false otherwise.
     * @since 1.3
     */
    public boolean isStartTLSEnabled() {
        return startTlsEnabled || tls;
    }

    /**
     * Tests whether the client is configured to require STARTTLS.
     *
     * @return true if using STARTTLS for authentication, false otherwise.
     * @since 1.3
     */
    public boolean isStartTLSRequired() {
        return startTlsRequired;
    }

    /**
     * Sends the email. Internally we build a MimeMessage which is afterwards sent to the SMTP server.
     *
     * @return the message id of the underlying MimeMessage
     * @throws IllegalStateException if the MimeMessage was already built, that is, {@link #buildMimeMessage()} was already called
     * @throws EmailException        the sending failed
     */
    public String send() throws EmailException {
        buildMimeMessage();
        return sendMimeMessage();
    }

    /**
     * Sends the previously created MimeMessage to the SMTP server.
     *
     * @return the message id of the underlying MimeMessage
     * @throws IllegalArgumentException if the MimeMessage has not been created
     * @throws EmailException           the sending failed
     */
    public String sendMimeMessage() throws EmailException {
        Objects.requireNonNull(message, "MimeMessage has not been created yet");
        try {
            Transport.send(message);
            return message.getMessageID();
        } catch (final Throwable t) {
            throw new EmailException("Sending the email to the following server failed : " + this.getHostName() + ":" + getSmtpPort(), t);
        }
    }

    /**
     * Sets the userName and password if authentication is needed. If this method is not used, no authentication will be performed.
     * <p>
     * This method will create a new instance of {@code DefaultAuthenticator} using the supplied parameters.
     * </p>
     *
     * @param userName User name for the SMTP server
     * @param password password for the SMTP server
     * @see DefaultAuthenticator
     * @see #setAuthenticator
     * @since 1.0
     */
    public void setAuthentication(final String userName, final String password) {
        this.setAuthenticator(new DefaultAuthenticator(userName, password));
    }

    /**
     * Sets the {@code Authenticator} to be used when authentication is requested from the mail server.
     * <p>
     * This method should be used when your outgoing mail server requires authentication. Your mail server must also support RFC2554.
     * </p>
     *
     * @param authenticator the {@code Authenticator} object.
     * @see Authenticator
     * @since 1.0
     */
    public void setAuthenticator(final Authenticator authenticator) {
        this.authenticator = authenticator;
    }

    /**
     * Sets a list of "BCC" addresses. All elements in the specified {@code Collection} are expected to be of type {@code java.mail.internet.InternetAddress}.
     *
     * @param collection collection of {@code InternetAddress} objects
     * @return An Email.
     * @throws EmailException Indicates an invalid email address
     * @see javax.mail.internet.InternetAddress
     * @since 1.0
     */
    public Email setBcc(final Collection<InternetAddress> collection) throws EmailException {
        EmailException.checkNonEmpty(collection, () -> "BCC list invalid");
        bccList = new ArrayList<>(collection);
        return this;
    }

    /**
     * Sets the "bounce address" - the address to which undeliverable messages will be returned. If this value is never set, then the message will be sent to
     * the address specified with the System property "mail.smtp.from", or if that value is not set, then to the "from" address.
     *
     * @param email A String.
     * @return An Email.
     * @throws IllegalStateException if the mail session is already initialized
     * @since 1.0
     */
    public Email setBounceAddress(final String email) {
        checkSessionAlreadyInitialized();
        if (!EmailUtils.isEmpty(email)) {
            try {
                bounceAddress = createInternetAddress(email, null, charset).getAddress();
            } catch (final EmailException e) {
                // Can't throw 'EmailException' to keep backward-compatibility
                throw new IllegalArgumentException("Failed to set the bounce address : " + email, e);
            }
        } else {
            bounceAddress = email;
        }

        return this;
    }

    /**
     * Sets a list of "CC" addresses. All elements in the specified {@code Collection} are expected to be of type {@code java.mail.internet.InternetAddress}.
     *
     * @param collection collection of {@code InternetAddress} objects.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address.
     * @see javax.mail.internet.InternetAddress
     * @since 1.0
     */
    public Email setCc(final Collection<InternetAddress> collection) throws EmailException {
        EmailException.checkNonEmpty(collection, () -> "CC list invalid");
        ccList = new ArrayList<>(collection);
        return this;
    }

    /**
     * Sets the charset of the message. Please note that you should set the charset before adding the message content.
     *
     * @param charset A String.
     * @throws java.nio.charset.IllegalCharsetNameException if the charset name is invalid
     * @throws java.nio.charset.UnsupportedCharsetException if no support for the named charset exists in the current JVM
     * @since 1.0
     */
    public void setCharset(final String charset) {
        final Charset set = Charset.forName(charset);
        this.charset = set.name();
    }

    /**
     * Sets the emailBody to a MimeMultiPart
     *
     * @param mimeMultipart aMimeMultipart
     * @since 1.0
     */
    public void setContent(final MimeMultipart mimeMultipart) {
        this.emailBody = mimeMultipart;
    }

    /**
     * Sets the content.
     *
     * @param content the content.
     * @return {@code this} instance.
     * @since 1.6.0
     */
    public Email setContent(final Object content) {
        this.content = content;
        return this;
    }

    /**
     * Sets the content and contentType.
     *
     * @param content     content.
     * @param contentType content type.
     * @since 1.0
     */
    public void setContent(final Object content, final String contentType) {
        this.content = content;
        updateContentType(contentType);
    }

    /**
     * Sets the content type.
     *
     * @param contentType the content type.
     * @return {@code this} instance.
     * @since 1.6.0
     */
    public Email setContentType(final String contentType) {
        this.contentType = contentType;
        return this;
    }

    /**
     * Sets the display of debug information.
     *
     * @param debug A boolean.
     * @since 1.0
     */
    public void setDebug(final boolean debug) {
        this.debug = debug;
    }

    /**
     * Sets the FROM field of the email to use the specified address. The email address will also be used as the personal name. The name will be encoded by the
     * charset of {@link #setCharset(String)}. If it is not set, it will be encoded using the Java platform's default charset (UTF-16) if it contains non-ASCII
     * characters; otherwise, it is used as is.
     *
     * @param email A String.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address.
     * @since 1.0
     */
    public Email setFrom(final String email) throws EmailException {
        return setFrom(email, null);
    }

    /**
     * Sets the FROM field of the email to use the specified address and the specified personal name. The name will be encoded by the charset of
     * {@link #setCharset(String)}. If it is not set, it will be encoded using the Java platform's default charset (UTF-16) if it contains non-ASCII characters;
     * otherwise, it is used as is.
     *
     * @param email A String.
     * @param name  A String.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address.
     * @since 1.0
     */
    public Email setFrom(final String email, final String name) throws EmailException {
        return setFrom(email, name, charset);
    }

    /**
     * Sets the FROM field of the email to use the specified address, personal name, and charset encoding for the name.
     *
     * @param email   A String.
     * @param name    A String.
     * @param charset The charset to encode the name with.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address or charset.
     * @since 1.1
     */
    public Email setFrom(final String email, final String name, final String charset) throws EmailException {
        fromAddress = createInternetAddress(email, name, charset);
        return this;
    }

    /**
     * Sets the From address.
     *
     * @param fromAddress the From address.
     * @return {@code this} instance.
     * @since 1.6.0
     */
    public Email setFromAddress(final InternetAddress fromAddress) {
        this.fromAddress = fromAddress;
        return this;

    }

    /**
     * Sets the mail headers. Example:
     *
     * X-Mailer: Sendmail, X-Priority: 1( highest ) or 2( high ) 3( normal ) 4( low ) and 5( lowest ) Disposition-Notification-To: user@domain.net
     *
     * @param map A Map.
     * @throws IllegalArgumentException if either of the provided header / value is null or empty
     * @since 1.0
     */
    public void setHeaders(final Map<String, String> map) {
        headers.clear();
        for (final Map.Entry<String, String> entry : map.entrySet()) {
            addHeader(entry.getKey(), entry.getValue());
        }
    }

    /**
     * Sets the hostname of the outgoing mail server.
     *
     * @param hostName aHostName
     * @throws IllegalStateException if the mail session is already initialized
     * @since 1.0
     */
    public void setHostName(final String hostName) {
        checkSessionAlreadyInitialized();
        this.hostName = hostName;
    }

    /**
     * Sets a mail Session object to use. Please note that passing a user name and password (in the case of mail authentication) will create a new mail session
     * with a DefaultAuthenticator. This is a convenience but might come unexpected.
     *
     * If mail authentication is used but NO user name and password is supplied the implementation assumes that you have set a authenticator and will use the
     * existing mail session (as expected).
     *
     * @param session mail session to be used
     * @throws NullPointerException if {@code aSession} is {@code null}
     * @since 1.0
     */
    public void setMailSession(final Session session) {
        Objects.requireNonNull(session, "no mail session supplied");

        final Properties sessionProperties = session.getProperties();
        final String auth = sessionProperties.getProperty(EmailConstants.MAIL_SMTP_AUTH);

        if (Boolean.parseBoolean(auth)) {
            final String userName = sessionProperties.getProperty(EmailConstants.MAIL_SMTP_USER);
            final String password = sessionProperties.getProperty(EmailConstants.MAIL_SMTP_PASSWORD);

            if (EmailUtils.isNotEmpty(userName) && EmailUtils.isNotEmpty(password)) {
                // only create a new mail session with an authenticator if
                // authentication is required and no user name is given
                authenticator = new DefaultAuthenticator(userName, password);
                this.session = Session.getInstance(sessionProperties, authenticator);
            } else {
                // assume that the given mail session contains a working authenticator
                this.session = session;
            }
        } else {
            this.session = session;
        }
    }

    /**
     * Sets a mail Session object from a JNDI directory.
     *
     * @param jndiName name of JNDI resource (javax.mail.Session type), resource if searched in java:comp/env if name does not start with "java:"
     * @throws IllegalArgumentException if the JNDI name is null or empty
     * @throws NamingException          if the resource cannot be retrieved from JNDI directory
     * @since 1.1
     */
    public void setMailSessionFromJNDI(final String jndiName) throws NamingException {
        if (EmailUtils.isEmpty(jndiName)) {
            throw new IllegalArgumentException("JNDI name missing");
        }
        Context ctx = null;
        if (jndiName.startsWith("java:")) {
            ctx = new InitialContext();
        } else {
            ctx = (Context) new InitialContext().lookup("java:comp/env");

        }
        setMailSession((Session) ctx.lookup(jndiName));
    }

    /**
     * Sets the MIME message.
     *
     * @param message the MIME message.
     */
    public void setMessage(final MimeMessage message) {
        this.message = message;
    }

    /**
     * Sets the content of the mail. It should be overridden by the subclasses.
     *
     * @param msg A String.
     * @return An Email.
     * @throws EmailException generic exception.
     * @since 1.0
     */
    public abstract Email setMsg(String msg) throws EmailException;

    /**
     * Sets whether to use POP3 before SMTP, and if so the settings.
     *
     * @param popBeforeSmtp whether to use POP3 before SMTP, and if so the settings.
     * @return {@code this} instance.
     * @since 1.6.0
     */
    public Email setPopBeforeSmtp(final boolean popBeforeSmtp) {
        this.popBeforeSmtp = popBeforeSmtp;
        return this;

    }

    /**
     * Sets details regarding "POP3 before SMTP" authentication.
     *
     * @param popBeforeSmtp Whether or not to log into POP3 server before sending mail.
     * @param popHost       The POP3 host to use.
     * @param popUserName   The POP3 user name.
     * @param popPassword   The POP3 password.
     * @since 1.0
     */
    public void setPopBeforeSmtp(final boolean popBeforeSmtp, final String popHost, final String popUserName, final String popPassword) {
        this.popBeforeSmtp = popBeforeSmtp;
        this.popHost = popHost;
        this.popUsername = popUserName;
        this.popPassword = popPassword;
    }

    /**
     * Sets the POP3 host.
     *
     * @param popHost The POP3 host.
     * @return {@code this} instance.
     * @since 1.6.0
     */
    public Email setPopHost(final String popHost) {
        this.popHost = popHost;
        return this;

    }

    /**
     * Sets the POP3 password.
     *
     * @param popPassword the POP3 password.
     * @return {@code this} instance.
     * @since 1.6.0
     */
    public Email setPopPassword(final String popPassword) {
        this.popPassword = popPassword;
        return this;

    }

    /**
     * Sets the POP3 user name.
     *
     * @param popUserName the POP3 user name.
     * @return {@code this} instance.
     * @since 1.6.0
     */
    public Email setPopUsername(final String popUserName) {
        this.popUsername = popUserName;
        return this;

    }

    /**
     * Sets a list of reply to addresses. All elements in the specified {@code Collection} are expected to be of type
     * {@code java.mail.internet.InternetAddress}.
     *
     * @param collection collection of {@code InternetAddress} objects
     * @return An Email.
     * @throws EmailException Indicates an invalid email address
     * @see javax.mail.internet.InternetAddress
     * @since 1.1
     */
    public Email setReplyTo(final Collection<InternetAddress> collection) throws EmailException {
        EmailException.checkNonEmpty(collection, () -> "Reply to list invalid");
        replyList = new ArrayList<>(collection);
        return this;
    }

    /**
     * Sets whether the email is partially send in case of invalid addresses.
     * <p>
     * In case the mail server rejects an address as invalid, the call to {@link #send()} may throw a {@link javax.mail.SendFailedException}, even if partial
     * send mode is enabled (emails to valid addresses will be transmitted). In case the email server does not reject invalid addresses immediately, but return
     * a bounce message, no exception will be thrown by the {@link #send()} method.
     * </p>
     *
     * @param sendPartial whether to enable partial send mode
     * @return An Email.
     * @throws IllegalStateException if the mail session is already initialized
     * @since 1.3.2
     */
    public Email setSendPartial(final boolean sendPartial) {
        checkSessionAlreadyInitialized();
        this.sendPartial = sendPartial;
        return this;
    }

    /**
     * Sets the sent date for the email. The sent date will default to the current date if not explicitly set.
     *
     * @param date Date to use as the sent date on the email
     * @since 1.0
     */
    public void setSentDate(final Date date) {
        if (date != null) {
            // create a separate instance to keep findbugs happy
            sentDate = new Date(date.getTime());
        }
    }

    /**
     * Sets the non-SSL port number of the outgoing mail server.
     *
     * @param portNumber aPortNumber
     * @throws IllegalArgumentException if the port number is &lt; 1
     * @throws IllegalStateException    if the mail session is already initialized
     * @since 1.0
     * @see #setSslSmtpPort(String)
     */
    public void setSmtpPort(final int portNumber) {
        checkSessionAlreadyInitialized();
        if (portNumber < 1) {
            throw new IllegalArgumentException("Cannot connect to a port number that is less than 1 ( " + portNumber + " )");
        }
        this.smtpPort = Integer.toString(portNumber);
    }

    /**
     * Sets the socket connection timeout value in milliseconds. Default is a 60 second timeout.
     *
     * @param socketConnectionTimeout the connection timeout
     * @throws IllegalStateException if the mail session is already initialized
     * @since 1.6.0
     */
    public void setSocketConnectionTimeout(final Duration socketConnectionTimeout) {
        checkSessionAlreadyInitialized();
        this.socketConnectionTimeout = Math.toIntExact(socketConnectionTimeout.toMillis());
    }

    /**
     * Sets the socket I/O timeout value in milliseconds. Default is 60 second timeout.
     *
     * @param socketTimeout the socket I/O timeout
     * @throws IllegalStateException if the mail session is already initialized
     * @since 1.6.0
     */
    public void setSocketTimeout(final Duration socketTimeout) {
        checkSessionAlreadyInitialized();
        this.socketTimeout = Math.toIntExact(socketTimeout.toMillis());
    }

    /**
     * Sets whether the server identity is checked as specified by RFC 2595
     *
     * @param sslCheckServerIdentity whether to enable server identity check
     * @return An Email.
     * @throws IllegalStateException if the mail session is already initialized
     * @since 1.3
     */
    public Email setSSLCheckServerIdentity(final boolean sslCheckServerIdentity) {
        checkSessionAlreadyInitialized();
        this.sslCheckServerIdentity = sslCheckServerIdentity;
        return this;
    }

    /**
     * Sets whether SSL/TLS encryption should be enabled for the SMTP transport upon connection (SMTPS/POPS). Takes precedence over
     * {@link #setStartTLSRequired(boolean)}
     * <p>
     * Defaults to {@link #sslSmtpPort}; can be overridden by using {@link #setSslSmtpPort(String)}
     * </p>
     *
     * @param ssl whether to enable the SSL transport
     * @return An Email.
     * @throws IllegalStateException if the mail session is already initialized
     * @since 1.3
     */
    public Email setSSLOnConnect(final boolean ssl) {
        checkSessionAlreadyInitialized();
        this.sslOnConnect = ssl;
        this.ssl = ssl;
        return this;
    }

    /**
     * Sets the SSL port to use for the SMTP transport. Defaults to the standard port, 465.
     *
     * @param sslSmtpPort the SSL port to use for the SMTP transport
     * @throws IllegalStateException if the mail session is already initialized
     * @see #setSmtpPort(int)
     */
    public void setSslSmtpPort(final String sslSmtpPort) {
        checkSessionAlreadyInitialized();
        this.sslSmtpPort = sslSmtpPort;
    }

    /**
     * Sets or disable the STARTTLS encryption.
     *
     * @param startTlsEnabled true if STARTTLS requested, false otherwise
     * @return An Email.
     * @throws IllegalStateException if the mail session is already initialized
     * @since 1.3
     */
    public Email setStartTLSEnabled(final boolean startTlsEnabled) {
        checkSessionAlreadyInitialized();
        this.startTlsEnabled = startTlsEnabled;
        this.tls = startTlsEnabled;
        return this;
    }

    /**
     * Sets or disable the required STARTTLS encryption.
     * <p>
     * Defaults to {@link #smtpPort}; can be overridden by using {@link #setSmtpPort(int)}
     * </p>
     *
     * @param startTlsRequired true if STARTTLS requested, false otherwise
     * @return An Email.
     * @throws IllegalStateException if the mail session is already initialized
     * @since 1.3
     */
    public Email setStartTLSRequired(final boolean startTlsRequired) {
        checkSessionAlreadyInitialized();
        this.startTlsRequired = startTlsRequired;
        return this;
    }

    /**
     * Sets the email subject. Replaces end-of-line characters with spaces.
     *
     * @param aSubject A String.
     * @return An Email.
     * @since 1.0
     */
    public Email setSubject(final String aSubject) {
        this.subject = EmailUtils.replaceEndOfLineCharactersWithSpaces(aSubject);
        return this;
    }

    /**
     * Sets a list of "TO" addresses. All elements in the specified {@code Collection} are expected to be of type {@code java.mail.internet.InternetAddress}.
     *
     * @param collection collection of {@code InternetAddress} objects.
     * @return An Email.
     * @throws EmailException Indicates an invalid email address.
     * @see javax.mail.internet.InternetAddress
     * @since 1.0
     */
    public Email setTo(final Collection<InternetAddress> collection) throws EmailException {
        EmailException.checkNonEmpty(collection, () -> "To list invalid");
        this.toList = new ArrayList<>(collection);
        return this;
    }

    /**
     * Converts to copy List of known InternetAddress objects into an array.
     *
     * @param list A List.
     * @return An InternetAddress[].
     * @since 1.0
     */
    protected InternetAddress[] toInternetAddressArray(final List<InternetAddress> list) {
        return list.toArray(EMPTY_INTERNET_ADDRESS_ARRAY);
    }

    /**
     * Updates the contentType.
     *
     * @param contentType aContentType
     * @since 1.2
     */
    public void updateContentType(final String contentType) {
        if (EmailUtils.isEmpty(contentType)) {
            this.contentType = null;
        } else {
            // set the content type
            this.contentType = contentType;
            // set the charset if the input was properly formed
            final String strMarker = "; charset=";
            int charsetPos = EmailUtils.toLower(contentType).indexOf(strMarker);
            if (charsetPos != -1) {
                // find the next space (after the marker)
                charsetPos += strMarker.length();
                final int intCharsetEnd = EmailUtils.toLower(contentType).indexOf(" ", charsetPos);
                if (intCharsetEnd != -1) {
                    this.charset = contentType.substring(charsetPos, intCharsetEnd);
                } else {
                    this.charset = contentType.substring(charsetPos);
                }
            } else if (this.contentType.startsWith("text/") && EmailUtils.isNotEmpty(this.charset)) {
                // use the default charset, if one exists, for messages
                // whose content-type is some form of text.
                final StringBuilder contentTypeBuf = new StringBuilder(this.contentType);
                contentTypeBuf.append(strMarker);
                contentTypeBuf.append(this.charset);
                this.contentType = contentTypeBuf.toString();
            }
        }
    }
}