Can GCJ only handle source code?
GCJ will compile both source (.java) and bytecode (.class) files. However, in many cases the native code produced by compiling from source is better optimized than that compiled from .class files. Per Bothner explains: The reason is that when you compile to bytecode you lose a lot of information about program structure etc. That information helps in generating better code. We can in theory recover the information we need by analysing the structure of the bytecodes, but it is sometimes difficult – or sometimes it just that no-one has gotten around to it. Specific examples include loop structure (gcc generates better code with explicit loops rather than with the equivalent spaghetti code), array initializers, and the JDK 1.1 `CLASS.class’ syntax, all of which are represented using more low-level constructs in bytecode.
