This book provides a high-level description, together with a mathematical and an experimental analysis, of Java and of the Java Virtual Machine (JVM), including a standard compiler of Java programs to JVM code and the security critical bytecode verifier component of the JVM. The description is structured into language layers and machine components. It comes with a natural executable refinement (written in AsmGofer and provided on CD ROM) which can be used for testing code. The method developed for this purpose is based on Abstract State Machines (ASMs) and can be applied to other virtual machines and to other programming languages as well. The book is written for advanced students and for professionals and practitioners in research and development who need a complete and transparent definition and an executable model of the language and of the virtual machine underlying its intended implementation.The CD ROM contains the entire text of the book and numerous examples and exercises.

The origin of this book goes back to the Dagstuhl seminar on Logic for System Engineering, organized during the first week of March 1997 by S. Jiihnichen, J. Loeckx, and M. Wirsing. During that seminar, after Egon Borger's talk on How to Use Abstract State Machines in Software Engineering, Wolfram Schulte, at the time a research assistant at the University of Ulm, Germany, questioned whether ASMs provide anything special as a scientifically well founded and rigorous yet simple and industrially viable framework for high level design and analysis of complex systems, and for natural refinements of models to executable code. Wolfram Schulte argued, referring to his work with K. Achatz on A Formal Object-Oriented Method Inspired by Fusion and Object-Z [1], that with current techniques of functional programming and of axiomatic specification, one can achieve the same result. An intensive and long debate arose from this discussion. At the end of the week, it led Egon Borger to propose a collaboration on a real-life specification project of Wolfram Schulte's choice, as a comparative field test of purely functional declarative methods and of their enhancement within an integrated abstract state-based operational (ASM) approach. After some hesitation, in May 1997 Wolfram Schulte accepted the offer and chose as the theme a high-level specification of Java and of the Java Virtual Machine.