MAJOR: Flexible Tool Development with

Developing and maintaining tools for profiling, debugging, testing, and reverse engineering can be difficult when using low-level techniques, such as bytecode instrumentation. We promote tool development in Java using high-level aspect-oriented programming. We demonstrate that the use of aspects yields concise tools that are easy to develop, extend, and maintain, because low-level instrumentation details are hidden from the developer. We introduce MAJOR, a new tool for comprehensive aspect weaving, which ensures that aspects are woven into all classes executing in a Java Virtual Machine, including those in the standard Java class library. MAJOR includes the pluggable module CARAJillo, which supports efficient access to a complete and customizable calling context representation. Both distinguishing features of MAJOR ‐ comprehensive aspect weaving and efficient access to complete calling information ‐ are essential in the aforementioned domains.