Challenges for code generated OCL execution.

While OCL is primarily a specification language supporting the elaboration of often-graphical metamodels with textual constraints, it is also executable enabling the constraints to be used to validate models. The superficial textual similarity of OCL and Java has tempted some authors to attempt a textual transliteration to facilitate a faster Java execution. Unfortunately there are many aspects of OCL semantics that deviate from Java and so transliteration is close to impossible. We identify the semantic differences so that new transliteration attempts can review the almost inevitable limitations of an OCL-like transliteration when choosing to implement a Java-Friendly OCL rather than a full OCL code generator.