ANTLR, "a language tool that provides a framework for constructing recognizers, compilers, and translators from grammatical descriptions containing Java, C#, C++, or Python actions" -- http://www.antlr.org
Make sure that the Eclipse Java compiler generates Java 5-compliant class files (the ASM and Bytecode outliner plugin does not support Java 6). To set this, open the Window->Preferences... menu item.
Expand Java in the preference tree, and select Compiler.
Make sure that the Compiler compliance level is set to 5.0.