Mixing JVM languages in a project

Many languages offer good interoperability with Java, and therefore, with other JVM languages as well. Languages do this if they use standard Java Class Library classes, where possible, for their data structures and compile methods in a similar way as Java would have done.

It's not uncommon to have certain classes compiled in a different language in a Java project. One should be aware of the various issues, though:

• It can complicate the building process a lot
• Many languages require their own runtime classes that can cause issues