As a Java programmer I would love a version of afl. The JVM certainly exposes enough information for other profilers/tracers and things dynamically adding code (spring/hibernate) that it seems like it should be possible.
There's a tool that does similar to AFL called EvoSuite (http://www.evosuite.org). It uses a genetic algorithm like AFL and generates JUnit suites for the target classes. It doesn't look for crashes like AFL - it's closer to MS's IntelliTest tool but uses metaheuristics instead of SMT to break conditions.