I have done the first round of https://jira.jboss.org/jira/browse/JBIDE-3883: 1) Added Bundle-RequiredExecutionEnvironment: J2SE-1.5 to manifest.mf of plugins that did not have it 2) Use Execution Environment in classpath instead of specific named JDK This revealed a few things though which we need to fix: a) usage of com.sun.* classes should removed (hibernate ui/diagram have this) b) we should remove .settings whereever possible since with1 and 2 from above it should no longer be necessary to set project specific compiler options; and having them overriden per project just creates confusion. Removing .settings will be my next cleanup - let me know if you know of a good reason for keeping any .settings files around ? /max