So I'm learning Java

[Vanilla]

Well, that depends. I don't know if you have C/C++ classes, but i suspect their failure rates would be higher than that of Java. And equally, Actionscript, Javascript and PHP would be lower. Also, if you are going to pickup such a hard language anyway, if would recommend C++ instead. Since it is bytecode compiled, you can achieve higher speeds, unlike Java which is interpreted in a virtual machine and thus slower, atleast a little.
I guess the hardest thing about Java in contrast to Javascript, is that you are almost forced to take a more object-oriented approach. OOP programming is harder to learn than traditional sequential programming, but it's well worth it ;)