Modular heterogeneous system development: a critical analysis of Java

Java supports heterogeneous applications by transforming a heterogeneous network of machines into a homogeneous network of Java virtual machines. This approach abstracts over many of the complications that arise from heterogeneity, providing a uniform API to all components of an application. However, for many applications heterogeneity is an intentional feature where components and resources are co-located for optimal performance. The authors argue that Java's API does not provide an effective means for building applications in such an environment. Specifically, they suggest improvements to Java's existing mechanisms for maintaining consistency (e.g. synchronized), and controlling resources (e.g. thread scheduling). They also consider the recent addition of a CORBA API in JDK 1.2. They argue that while such an approach provides greater flexibility for heterogeneous applications, many key problems still exist from an architectural standpoint. Finally, they consider the future of Java as a foundation for component-based software in heterogeneous environments and suggest architectural abstractions which will prove key to the successful development of such systems. They drive the discussion with examples and suggestions from their work on the Actor model of computation.