Is there anyway I can learn java on my phone? ?

I have a Nexus so 4g, I had to buy in replacement of my evo 4g. I live off my phphone, doing everything from ftp work, to messaging, email, and even manage my CSS server. Basically I'm never on my computer but to game and that's 2nd times a week. I want to learn java to program some apps. I know basic htmlhtml and whatever script Valve uses on there source engine. Can anyone think of an app, or a way to run java code after reading through an actual book?