From sequential to multi-threaded Java: An event-based operational semantics

Abstract

A structural operational semantics of a non trivial sublanguage of Java is presented. This language includes dynamic creation of objects, blocks, and synchronization of threads. First we introduce a simple operational description of the sequential part of the language, where the memory is treated as an algebra with suitably axiomatized operations. Then, the interaction between threads via a shared memory is described in terms of structures, called “event spaces,” whose wellformedness conditions formalize directly the rules given in the Java language specification. Event spaces are included in the operational judgements to develop the semantics of the full multi-threaded sublanguage, which is shown to extend the one for sequential Java conservatively. The result allows sequential programs to be reasoned about in a simplified computational framework without loss of generality.