This book constitutes the refereed proceedings of the 7th International Conference on the Unified Modeling Language, UML 2004, held in Lisbon, Portugal, in October 2004.

The 30 revised full papers presented together with summaries on the workshops and tutorials were carefully reviewed and selected from 135 technical paper submissions. The papers are organized in topical sections on metamodeling, aspects, profiles and extensions, OCL, model transformation, verification and model consistency, security, and methodology.

Metamodel evolution is rarely driven by empirical evidences of metamodel drawbacks. In this paper, the evolution of the use case metamodel used by the publicly available requirements management tool REM is presented. This evolution has been driven by the analysis of empirical data obtained during the assessment of several metrics–based verification heuristics for use cases developed by some of the authors and previously presented in other international fora. The empirical analysis has made evident that some common defects found in use cases developed by software engineering students were caused not only by their lack of experience but also by the expressive limitations imposed by the underlying use case metamodel used in REM. Once these limitations were clearly identified, a number of evolutionary changes were proposed to the REM use case metamodel in order to increase use case quality, i.e. to avoid those situations in which the metamodel were the cause of defects in use case specifications.