Ui, you want to write a virus, spyware? ;-)

Fortunately Java is not well suited for this kind of system
"programming". Consider using another programming language. Or even
better, consider spending your time for better things than snooping data
and invading user's privacy.

/Thomas

A Java application will keep runing as long as it still has some threads
alive, or the main method is not completed.

To avoid being seen, don't create any frames, and archive the classes into a
JAR, and specify the Main-Class attribute inside the manifest. By installing
the Java plug-in, it will create the file association of JAR files to javaw,
which executes the main class inside the JAR without a console. Google
"Executable Jar" for how to create that... for example,
http://www.captain.at/programming/java/executable-java-application.php is
one of the search results.

Of course user can change their file association and ruin the executable jar
method, but really how often does that happen? Many users don't even tidy up
their start menu and destop... and to work around that, you can always
create a shortcut to javaw with proper parameters for them.

Keeping track of user opening any .exe file, is the big problem. I don't
have any good (and clean) idea about it right now.

uvdhanya@rediffmail.com wrote in comp.lang.java.gui:

    You can't do this with Java. It is simply impossible. Use some
    other language instead.