Understanding the Impact of Collection Contracts on Design

  • Stephen Nelson
  • David J. Pearce
  • James Noble
Part of the Lecture Notes in Computer Science book series (LNCS, volume 6141)


Java provides a specification for a user-defined general purpose equivalence operator for objects, but collections such as Set have more stringent requirements. This inconsistency breaks polymorphism: programmers must take care to follow Set’s contract rather than the more general Object contract if their object could enter a Set. We have dynamically profiled 30 Java applications to better understand the way programmers design their objects, to determine whether they program with collections in mind. Our results indicate that objects which enter collections behave very differently to objects which do not. Our findings should help developers understand the impact of design choices they make, and guide future language designers when adding support for collections and/or equality.


Object Identity Benchmark Suite Object Graph Java Application Standard Library 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • Stephen Nelson
    • 1
  • David J. Pearce
    • 1
  • James Noble
    • 1
  1. 1.Victoria University of WellingtonWellingtonNew Zealand

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