Is Python a possible alternative for Java

One of the language I evaluated as an alternative to Java of course was Python despite my hatred for languages that have significant white spaces. I did not get very far. In general, the syntax of the language is ok (except for whitespace) but the problem is speed. CPython is terribly slow as in unacceptably slow so I looked at PyPy since this uses a JIT compiler. No luck. It is better that CPython but it is not a substitute for it. You simply cannot assume that the program you ran in CPython will run with PyPy. Some libraries do not run with the JIT and there are a few other incompatibilities. So, Python will not be the successor for Java in my book. What would be your choice of multi-platform open source programming language (really open source - no license for embedded systems) ?