The runtime environment includes a JIT compiler developed by Symantec, the standard Java class library from Sun, additional classes providing Macintosh-specific functionality, and the Apple Applet Runner (a lightweight application for running Java applets without the overhead of a web browser). Both a runtime environment and a software development kit (SDK) are available.
Mac OS Runtime for Java ( MRJ, originally Macintosh Runtime for Java) was Apple's proprietary virtual machine for Java-based applications in the classic Mac OS (i.e.
