ubuntu netbeans: javadoc popup fail -- solved

after a recent upgrade to the ubuntu java* packages, netbeans' javadoc popup for core java, eg java.lang.Class.*, wasn't working. showed "no comments found"

solved: under Tools --> Java Platform --> Sources :: remove any existing sources and add /usr/lib/jvm/java-6-sun/src.zip (if you're not on ubuntu, then the path to the source, i guess :)

related note: had another problem a few days ago with the debugger bombing out after an upgrade to netbeans. solved: remove all breakpoints