Checking ownership and confinement

A number of proposals to manage aliasing in Java-like programming languages have been advanced over the last five years. It is not clear how practical these proposals are, that is, how well they relate to the kinds of programs currently written in Java-like languages. To address this problem, we analysed heap snapshots from a corpus of Java programs. Our results indicate that object-oriented programs do in fact exhibit symptoms of encapsulation in practice, and that proposed models of uniqueness, ownership, and confinement can usefully describe the aliasing structures of object-oriented programs. Understanding the kinds of aliasing present in programs should help us to design formalisms to make explicit the kinds of aliasing implicit in object-oriented programs.