What sense does it make to speak of a language as being interpreted or compiled? These are attributes of an implementation. The existence of GCJ, a native-code Java compiler that's been around for years, proves this.

It's true there are languages that are essentially uncompilable, and so have to be interpreted. Perl is the best example I can think of; there are constructs in the language that can't be parsed correctly without runtime context. Python, Ruby, and JavaScript are all difficult to do AoT compilation on as well, at least if you want to do much optimization, but I wouldn't agree that they can't be compiled. But Java is not as dynamic as these languages.