Why do we need other JVM languages

Question

I see here that there are a load of languages aside from Java that run on the JVM. I\'m a bit confused about the whole concept of other languages running in the JVM. So:

Answer 1

The reason is that the JVM platform offers a lot of advantages.

• Giant number of libraries
• Broader degree of platform implementations
• Mature frameworks
• Legacy code that's already part of your infrastructure

The languages Sun is trying to support with their Scripting spec (e.g. Python, Ruby) are up and comers largely due to their perceived productivity enhancements. Running Jython allows you to, in theory, be more productive, and leverage the capabilities of Python to solve a problem more suited to Python, but still be able to integrate, on a runtime level, with your existing codebase. The classic implementations of Python and Ruby effect the same ability for C libraries.

Additionally, it's often easier to express some things in a dynamic language than in Java. If this is the case, you can go the other way; consume Python/Ruby libraries from Java.

There's a performance hit, but many are willing to accept that in exchange for a less verbose, clearer codebase.