JavaMail : Java Glossary

JAF (Java Activation Framework) is now bundled with the JDK (Java Development Kit) . If you are using an older Java, to install JAF, open the download with WinZip and extract all files with folder names to the Program Files directory of some drive. Ditto for JavaMail. As of Java version 1.6, JAF is bundled with the JDK. Then make sure "J:\Program Files\jaf-1.1.1\activation.jar" and "J:\Program Files\javamail-1.5.6\javax.mail.jar" are explicitly mentioned in your classpath, (not just in a classpath directory!). Alternatively, add the jars to the ext directory.

You won’t likely directly use the JAF java.activation package, but JavaMail uses them. JavaMail also comes bundled with JavaEE.

Look on your local hard disk in the JAF downloaded docs J:\Program Files\jaf1.1.1\docs\javadocs\index.html or

JavaMail and JAF docs are not part of the JDK, but the source comes with EE (Enterprise Edition). JavaMail does not support the Windows proprietary MAPI (Messaging API) protocol. Oracle’s implementation of JavaMail is now open source.

JavaMail also supports Google Gmail and Yahoo mail.

The tutorial is the best way to get started, since it explains how all the classes fit together. The API docs give a lot of detail, but nothing on how it all fits together. Another way to understand it is to look at the demo examples, particularly msgsend.java to send and msgshow.java to receive. The term store refers to all your messages stored on the server’s hard disk. The term folder refers to the mail messages stored on the mail server in the SMTP INBOX. Folder. getMessages just gets message headers. MimeMessage. getContent gets the message body.

Installing JavaMail

1. 
2. Unzip
3. Put a copy of javax.mail.jar in each of your ext directories, such as:
   ext directories :

   • in C:\Program Files\java\jre1.8.0_131\lib\ext\ in JRE 1.8.0_131 on your local Windows C: drive.
   • in J:\Program Files\java\jdk1.8.0_131\jre\lib\ext\ in JDK 1.8.0_131 on your local Windows J: drive.
   • in X:\Program Files (x86)\jet12.0-pro-x86\profile1.8.0_131\jre\lib\ext\ in Jet jet12.0-pro-x86/1.8.0_131 on your local Windows X: drive.
   • in X:\Program Files\JetBrains\IntelliJ IDEA 2017.3\jre\jre\lib\ext\ in IntelliJ Idea IntelliJ IDEA 2017.3 on your local Windows X: drive.

Coding Tips

If you get a Message, you can’t close the Folder or Session until you are completely finished grabbing fields for the Message. Once the Session is gone, you can’t get any additional information about the Message. This is not that unusual, but it means you can’t write a method to return a Message object unless either:

1. All the Message’s interesting fields have already been probed and cached.
2. You keep the Session and Folder open. Until the caller is finished with the Message object.
3. You can get a free account to experiment with IMAP (Internet Message Access Protocol) from FastMail.

Similarly you need to hold Folder and Session open in order to be able to later delete the Message from the server.

Most JavaMail applications involve reading a message and modifying it in some way and sending it on. Most mail servers will not permit you to modify the incoming message. You must create a new one and copy the parts over. There are three techniques you can use to copy.

1. Part.getContent Part.setContent
2. Part.getDataHandler Part.setDataHandler
3. Multipart.getBodyPart Multipart.addBodyPart

You probably want to use transport.sendMessage ( message, recipients ), not Transport. send( message );

Often

message.setFlag( Flags.Flag.SEEN, true );
message.setFlag( Flags.Flag.DELETED, true );

JavaMail In Applets

Awkward Characters

JavaMail is does not provide a mailserver. You might use something like James rather that using your ISP (Internet Service Provider) ’s mailserver.

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