Parameterized types for Java

Abstract

Java offers the real possibility that most programs can be written in a type-safe language. However, for Java to be broadly useful, it needs additional expressive power. This paper extends Java in one area where more power is needed: support for parametric polymorphism, which allows the definition and implementation of generic abstractions. The paper discusses both the rationale for our design decisions and the impact of the extension on other parts of Java, including arrays and the class library. It also describes an implementation of the mechanism, including extensions to the Java virtual machine, and designs for the bytecode verifier and interpreter. The bytecode interpreter has been implemented; it provides good performance for parameterized code in both execution speed and code size, and does not slow down programs that do not use parameterized code.

Towards a Java Subtyping Operad

“…Much of this research was done before generics were added to Java. For example, the work in [8,7,10,16,47] was mostly focused on researching OO generics, while the work in [18,20,19,21] was focused on type safety. Some research on generics, and generic type inference, was also done after generics were added to Java, e.g., [40,50,4,26].…”

Late data layout

“…While this has an associated runtime cost [62], several solutions have been proposed to reduce it: in the CLR, reified types are computed lazily [35]. In Java, several papers presented viable schemes for carrying reified types, including PolyJ [11], Pizza [47], NextGen [19] and the work by Viroli et al [76]. Finally, in ML, generic code (also called parametrically polymorphic in functional languages) can carry explicit type representations [30,71].…”

Type-based race detection for Java

“…There have been many suggested language extensions for supporting Java classes parameterized by types [OW97,BOSW98,AFM97,BLM96,CJ98]. Our work uses a different notion of parameterization, namely, classes parameterized by values (more specifically, lock expressions).…”