Classpath

GNU Classpath is an attempt to create a free implementation of the standard class library for Java. It is a part of the Free Software Foundation's GNU project. Despite the massive size of the library to be replicated, the majority of the task is done aside from a portable Swing implementation.

GNU Classpath is used by many Free Software Java Virtual Machine projects (like Kaffe, SableVM, and GCJ) because every full-featured Java Virtual Machine must provide an implementation of the standard class libraries.

GNU Classpath is licensed under the GPL with Linking Exception.