We have thus far discussed many critical uses of Java in both client interfaces and middle-tier servers to high-performance systems. Here, we focus on the direct use of Java as a scientific and engineering programming language [26], taking the role currently played by Fortran 77, Fortran 90, and C++. (In our three-tier architecture, this is the use of Java in lower-tier engineering and science applications or in a CORBA vertical facility designed to support high-performance computing.)