I'm a big fan of the Lisp family of languages. If you want a modern Lisp, then I suggest to take a look at
Clojure. It runs on the JVM, has great interoperability with Java and has a very supportive community.
That said, you may find it easier to learn one new thing at a time. If you don't already know Lisp/Scheme/Clojure, you may spend a lot of time searching for trivial things like file IO, instead of thinking how to write the compiler.