After working nearly a decade on the design, development, and implementation of the Fortress programming language, the Oracle Labs Programming Language Research Group is now winding down the Fortress project. Ten years is a remarkably long run for an industrial research project (one to three years is much more typical), but we feel that our extended effort has been worthwhile. Many aspects of the Fortress design were novel, and we learned a great deal from building an interpreter and an initial set of libraries. Nevertheless, over the last few years, as we have focused on implementing a compiler targeted to the Java Virtual Machine, we encountered some severe technical challenges having to do with the mismatch between the (rather ambitious) Fortress type system and a virtual machine not designed to support it (that would be every currently available VM, not just JVM).
Steele goes on to thank DARPA for funding the project and then cites some of the valuable lessons learned for future programming languages. Read the Full Story.