On performance of delegation in Java

摘要

Delegation is an important design concept in object-oriented languages. In contrast to inheritance, which relates classes to each other, delegation operates on the level of objects and thus provides more flexibility. It is well known, that usage of delegation imposes performance penalties in the sense of delayed execution. But delegation on the level of sourcecode is optimized on bytecode level up to a degree, that imposes much lower performance penalties than expected. This paper examines in detail how big these penalties are.