Enforcing reference and object immutability in Java.

Immutability information is useful in many software engineering tasks, such as modeling, verification, optimization, and refactoring. Furthermore, undesired mutation or side-effect are hard to detect and debug. This paper describes a javac plug-in that enables programmers to write immutability annotations in a Java program to detect and prevent bugs. The IGJ annotations are rich and flexible; the tools are scalable; case studies show they are effective and easy to use; and the annotated program remains compilable with a standard compiler.