If you’ve installed both GCJ & Sun JDK installed on the same Ubuntu Linux install then you might have the problem I add. I installed both Eclipse and NetBeans and now the default Java Runtime was set to GCJ. To fix this you just have to try run the following:
update-java-alternatives –set java-1.5.0-sun
This should switch everything to use the Sun JRE. Found this info on the Java – Ubuntu Community Documentation.