Polymorphism in the Spotlight: Studying its Prevalence in Java and Smalltalk

Subtype polymorphism is a cornerstone of object-oriented programming. By hiding variability in behavior behind a uniform interface, polymorphism decouples clients from providers and thus enables genericity, modularity and extensi- bility. At the same time, however, it scatters the implementation of the behavior over multiple classes thus potentially hampering program comprehension. The extent to which polymorphism is used in real programs and the impact of polymorphism on program comprehension are not very well understood. We report on a preliminary study of the prevalence of polymorphism in several hundred open source software systems written in Smalltalk, one of the oldest object-oriented programming languages, and in Java, one of the most widespread ones. Although a large portion of the call sites in these systems are polymorphic, a majority have a small number of potential candidates. Smalltalk uses polymorphism to a much greater extent than Java. We discuss how these findings can be used as input for more detailed studies in program comprehension and for better developer support in the IDE.

An analysis of some Eulerian methods for one dimensional, inviscid, compressible hydrodynamics,

"Supported in part by the Advanced Research Projects Agency as administered by the Rome Air Development Center under contract no. US AF 30(602) 4144."

Stability and convergence of general multistep and multivalue methods with variable step size.

Thesis--University of Illinois.

A new class of digital division methods /

"This work was supported in part by the Atomic Energy Commission and the Office of Naval Research under AEC Contract AT(11-1)-415."

Numerical solution of stiff ordinary differential equations using collocation methods /

Bibliography: p. 79-80.

High order stiffly stable methods for ordinary differential equations

Supported in part by contract U.S. AEC AT(11-1) 1469 and in part by National Science Foundation grant NSF-GJ-217.

Methods for automatic error analysis of numerical algorithms /

Vita.

Multi-derivative numerical methods for the solution of stiff ordinary differential equations /

"Under contracts US AEC AT(11-1)2383 and US AEC AT(11-1)1469."

A note on the non-existence of multivalue A-stable methods of order greater than two /

Bibliography: leaf 3.

Iterative and direct methods for solving Poisson's equation and their adaptability to ILLIAC IV,

Includes bibliography.

Pruning and branching methods for designing optimal networks by the branch-and-bound method

Includes bibliographical references.

The effect of variable mesh size on the stability of multistep methods /

Bibliography: leaf 33.

Learning and generalization of structural descriptions : evaluation criteria and comparative review of selected methods /

"February 1980."

On Newton-iterative methods for the solution of systems of nonlinear equations /

Based on the author's thesis, Yale.

Stability and convergence of variable order multistep methods,

Includes bibliographical references.