c ACM, to be published in the July 2003 issue of TOPLAS. Preprint of nal version. Automatic Program Specialization for Java

The object-oriented style of programming facilitates program adaptation and enhances program genericness, but at the expense of eciency. We demonstrate experimentally that state-of-the-art Java compilers fail to compensate for the use of object-oriented abstractions in the implementation of generic programs, and that program specialization can eliminate a signicant portion of these overheads. We present an automatic program specializer for Java, illustrate its use through detailed case studies, and demonstrate experimentally that it can signicantly reduce program execution time. Although automatic program specialization could be seen as being subsumed by existing optimizing compiler technology, we show that specialization and compiler optimization are in fact complementary