protected void finalize() throws Throwable {...}

// Force finalize methods to be run on exit
// Without this, unreachable objects may not
// have had finalize run when you quit.
System.runFinalizersOnExit( true );

You can also register a hunk of code to be run like this:

Runtime.addShutdownHook( Thread hook );

Some feel finalize should be deprecated, and you should use phantom references instead since they give much better performance. Finalizers interfere with garbage collection. Their main use is debugging. Use them to issue an error message is an object is garbage collected without its close(), dispose(), disconnect()… method being called.