javac for better or worse is aggressively against doing optimizations to the point of producing the most ridiculously bad code. The belief tends to be that the JIT will do a better job fixing it if it has byte code that's as close as possible to the original code. But this only helps if a) the code ever gets JIT'd at all (rarely true for eg class initializers), and b) the JIT has the budget to do that optimization. Although JITs have the advantage of runtime information, they are also under immense pressure to produce any optimizations as fast as possible. So they rarely do the level of deep optimizations of an offline compiler.

Why should compiler optimize obviously dumb code? If developer wants to create billions of heap objects, compiler should respect him. Optimizing dumb code is what made C++ unbearable. When you write one code and compilers generates completely different code.