I have a huge legacy project that consists of many modules, and some of those have to be built against JDK7, others might be build for JDK8. There are few issues with the legacy code that prevent me to setup everything to be built against JDK8 with source level 7 (it's hard to explain, but during the code generation and GWT compilation I have all sort of errors related to JMockit of 0.999* that uses bytecode-alteration tweaks for tests)
In short - is there any way to specify that Maven has to use jdk8 for the module A, and jdk7 for the module B at compile-time?