Supporting Binary Compatibility with Static Compilation

There is an ongoing debate in the Java community on whether statically compiled implementations can meet the Java specification on dynamic features such as binary compatibility. Static compilation is sometimes desirable because it provides better code optimization, smaller memory footprint, more robustness, and better intellectual property protection. Unfortunately, none of the existing static Java compilers support binary compatibility, because it incurs unacceptable performance overhead. In this paper, we propose a simple yet effective solution which handles all of the binary-compatibility cases specified by the Java Language Specification. Our experimental results using an implementation in the GNU Java compiler shows that the performance penalty is on average less than 2%. Besides solving the problem for static compilers, it is also possible to use this technique in JIT compilers to achieve an optimal balance point between static and dynamic compilation.