What does the keyword "transient" mean in Java?

I saw somewhere

transient private TrackDAO trackDAO;

Google is your friend - first hit - also you might first have a look at what serialization is.

> It marks a member variable not to be > serialized when it is persisted to > streams of bytes. When an object is > transferred through the network, the > object needs to be 'serialized'. > Serialization converts the object > state to serial bytes. Those bytes are > sent over the network and the object > is recreated from those bytes. Member > variables marked by the java transient > keyword are not transferred, they are > lost intentionally.

Example from there, slightly modified (thanks @pgras):

public class Foo implements Serializable
 {
   private String saveMe;
   private transient String dontSaveMe;
   private transient String password;
   //...
 }

Transient variables in Java are never serialized.

It means that trackDAO should not be serialized.