MetaJava: an efficient run-time meta architecture for JavaTM

Adaptability to special requirements of applications is a crucial concern of modern operating system architectures. Reflection and meta objects are means to achieve this adaptability. We report on ideas and experience we obtained while extending the run-time system of the object-oriented language Java with reflective capabilities. We explain our model of an object-oriented architecture that allows flexible and selective attachment of reflective properties to objects. We show how reflection can be obtained with minimal changes to the existing system and how the penalty in run-time performance can be minimized. Our architecture is not limited to special application domains like distributed or concurrent computing but can also be used to support different security policies, just-in-time compilation, location control of mobile objects, etc. As an example, a remote method invocation mechanism is described to demonstrate how the Java programming model can be enhanced using our meta architecture