MultiJava: Design Rationale,
               Compiler Implementation, and Applications
                                  by
 Curtis Clifton, Todd Millstein, Gary T. Leavens, and Craig Chambers

                               Abstract

MultiJava is a conservative extension of the Java programming language that adds
symmetric multiple dispatch and open classes.  Among other benefits, multiple
dispatch provides a solution to the binary method problem.  Open classes provide
a solution to the extensibility problem of object-oriented programming
languages, allowing the modular addition of both new types and new operations to
an existing type hierarchy.  This paper illustrates and motivates the design of
MultiJava and describes its modular static typechecking and modular compilation
strategies.  Although MultiJava extends Java, the key ideas of the language
design are applicable to other object-oriented languages, such as C# and C++,
and even, with some modifications, to functional languages such as ML.

This paper also discusses the variety of application domains in which MultiJava
has been successfully used by others, including pervasive computing, graphical
user interfaces, and compilers. MultiJava allows users to express desired
programming idioms in a way that is declarative and supports static
typechecking, in contrast to the tedious and type-unsafe workarounds required in
Java.  MultiJava also provides opportunities for new kinds of extensibility that
are not easily available in Java.