One of Java's important advantages over other languages is that it will be learned and used by a broad group of users. Java is already being adopted in many entry-level college programming courses and will surely be attractive for teaching in middle or high schools. We believe that entering college students, fresh from their Java classes, will reject Fortran as quite primitive in contrast. C++, as a more complicated systems-building language, may well be a natural progression; but although it is quite heavily used, C++ has limitations as a language for simulation. In particular, it is hard for C++ to achieve good performance even on sequential code. We expect that Java will not have these problems.