I don't know how to do it myself but I'm certain this has been asked - and
answered - on one of the comp.lang.java.* newsgroups in the past, probably
this one.

Do a Google Groups search and you should be able to find it easily enough.

--
Rhino

You need a package called Jimi  http://java.sun.com/products/jimi/

Simple example at http://www.rgagnon.com/javadetails/java-0266.html 

Bye.

An interesting read:
http://today.java.net/pub/a/today/2006/04/20/bringing-swing-to-the-web.html

As has been discussed here many times, you can't in a general way. You
need to know the entity behind the Graphics context (where the
Graphics[2D] object came from). That entity might buffer, and it might
provide methods to fetch that buffer. But there is no guarantee.

/Thomas

One simple way is to create a BufferedImage, get a Graphics from it and
pass it to the drawing method.  Then save the BufferedImage to a file.
Of course this assumes that your drawing method doesn't do a bunch of
other stuff that will mess this up.