- Eclipse OCL was originally Java-based using runtime parsing and interpretation, but is moving to using model-to-text generation to directly generate Java code for improved performance. - The new Eclipse OCL architecture in Juno uses the Xtext editor to embed OCL text and the Pivot model to represent OCL at runtime, generating Java code via Acceleo templates rather than interpreting OCL. - OCL is an executable constraint language standardized by OMG, while Xbase is a Java-like implementation language supported by Eclipse; both are almost useless without being embedded in a modeling context.