Ive previously done iOS development (on the side) and tried Android development in the last few weeks and it feels like a massive, horrible hacked together pipe

Ive previously done iOS development (on the side) and tried Android development in the last few weeks and it feels like a massive, horrible hacked together pipeline. Why go through this horrible hack of a pipeline, recompiling and modifying .class files when you can instead create a compiler which does it directly?