micro-libgcj is a lightweight version of the GCJ project's runtime library (libgcj), intended to provide a usable subset of Java's features while remaining small and self-contained. Whereas libgcj is intended to be a complete J2SE implementation based on GNU Classpath, micro-libgcj provides only the common subset of functionality required by most programs.
micro-libgcj contains a subset of the runtime support and classpath provided by libgcj. The classes included in the classpath remain compatible with their Java counterparts wherever size and simplicity allow, but are otherwise much reduced. Besides the core Java language semantics, micro-libgcj provides: