Code in FEELImpl could be reused in the DMNFEELHelper, but it cannot be shared, because FEELImpl exposes an interface to evaluate expressions, while DMNFEELHelper needs access to the compiler backend.

Solution: separate the compilation pipeline and the interpreter pipeline from the public FEEL interface to promote code reuse. In particular, CompilerBytecodeLoader can be probably split between some kind of CompiledUnit+CompiledUnaryTest impls that provide methods to retrieve Java source code and/or JVM bytecode.