The canonical implementation of ACT-R is written in the LISP programming language. Although LISP has served the community well for years, its extensibility for different task implementations and different hardware platforms has been lagging compared to more modern languages. In contrast, Java is extremely portable to different platforms and facilitates the development of sophisticated task environments through its many built-in and third-party packages. In fact, a Java implementation of ACT-R already exists -- jACT-R -- which demonstrates some of Java's advantages in portability and modularity.
This new Java implementation of ACT-R is intended to provide an alternative to the LISP implementation. While the LISP version remains the canonical version of the architecture, the new Java version aims to be as faithful as possible to the underlying cognitive theory. It also strives to provide easy access to the cognitive theory via an integrated development environment, in which a user can write and run models in a simple application, but can also develop custom code and modules when necessary.