You can always run more... civilized languages on top of the JVM, talking to Java classes without problem.

For this movie they should have made PG the dad and his son decides to use Java instead of Lisp.

In what way does the JVM "not work"?

I remember the days when the JVM only had mark and sweep GC and it interpreted bytecodes. I remember when the JIT kept on crashing, and Java apps were catching up to Smalltalk VMs on benchmarks, but wheezing on real apps because of poor GC. Then there was generational GC, but lots of real apps were still wheezing because no one knew how to tune the GC settings. It took a decade for the JVM to cover the same ground the Smalltalk VMs had covered 4 or 5 before it.

Now the JVM is mature, and it fricken kicks ass! Really, for a high-level OO language supporting VM, the thing just screams. It's still unwieldy and much better suited to server stuff, but as a Smalltalker and therefore a former longtime Java detractor, I have to say, I am really impressed.

So, putting it shortly, it does work.

I agree completely Smalltalk 80 kicks Java 2010's ass, but, still, saying Java does not work is kind of exaggerated.

Resource Management, and stability.