Byte Code Engineering

The term “Java” is used to denote two different concepts: the language itself and the related execution environment, the Java Virtual Machine (JVM), which executes byte code instructions. Several research projects deal with byte code-generating compilers or the implementation of new features via byte code transformations. Examples are code optimization, the implementation of parameterized types for Java, or the adaptation of run-time behavior through load-time transformations. Many programmers are doing this by implementing their own specialized byte code manipulation tools, which are, however, restricted in the range of their reusability. Therefore, we have developed a general purpose framework for the static analysis and dynamic creation or transformation of byte code. In this paper we present its main features and possible application areas.