I by mistake today did an svn add from the root folder - which added all .java as well as .class files.
I could do an svn revert easily, but that will revert the changes I did for existing files as well - which I do not want to happen.
So - following is the one I came up with and works really handy - and thought of sharing.
From the root folder...
$ find . -name '*.class' | xargs svn revert