Java class files (compiled Java) can be decompiled. Unless they ran the code through an obfuscator or something in the android dev cycle does that automaticall

Java class files (compiled Java) can be decompiled. Unless they ran the code through an obfuscator or something in the android dev cycle does that automatically (I don't know), you can get the full source with full variable names, more or less. The stock javac compiler doesn't do much in terms of optimization, there are a couple things it does (replaces accesses to 'final static' members with constants for example), most is left to the JIT, bytecode -> source translation is pretty straight forward and you don't lose much.