An object-oriented, concurrent, reflective language based on hybrid group architecture. ABCL/R2 was produced by <masuhara@is.s.u-tokyo.ac.jp>, <matsu@is.s.u-tokyo.ac.jp>, <takuo@is.s.u-tokyo.ac.jp>, <yonezawa@is.s.u-tokyo.ac.jp>, at the tokyo institute of technology in 1992.

As a reflective language, an ABCL/R2 program can dynamically control its own behaviour, such as scheduling policy, from within a user-program. This system has almost all functions of abcl/1 and is written in common lisp.