jEdit-4.2 doesn't compile with JDK 1.5. It gives thousands of errors so it is probably code problems. Anyway I think the ebuild should warn if the user has JDK 1.5 as prefered compiler. Reproducible: Always Steps to Reproduce:
1.5 is package masked meaning it doesn't work correctly
Indeed 1.5 is masked. However, even the release will probably not work because of the changes done to Java 1.5.
The solution is to provide the "-source 1.4" compiler option. This makes the java compiler to accespt java 1.4 code. The default is to only accept 1.5 code.