Poor Man's Genericity for Java

A number of proposals have been made as to how Java can be changed to support parameterized types. We present a new proposal that does not try to provide more powerful constructs or cleaner semantics, but instead minimizes the changes that need to be made to existing Java compilers. In particular, we found that changing only one method in Sun’s Java compiler already results in a reasonable implementation of parameterized types, which we call “Poor Man’s Genericity” (PMG). We have implemented our solution based on simple byte-code transformations both at compile-time and at load-time. The paper explains how our solution works, and compares it to other proposals. We also describe how the drawbacks of our approach can be overcome by making additional, but minimal changes to an existing Java compiler.