Exception handling: Expecting the unexpected

Since the mid-1970s, and with the development of each new programming paradigm there has been an increasing interest in exceptions and the benefits of exception handling. With the move towards programming for ever more complex architectures, understanding basic facilities such as exception handling as an aid to improving program reliability, robustness and comprehensibility has become much more important. Interest has sparked the production of many papers both theoretical and practical, each giving a view of exceptions and exception handling from a different standpoint. In an effort to provide a means of classifying exception handling models which may be encountered, a taxonomy is presented in this paper. As the taxonomy is developed some of the concepts of exception handling are introduced and discussed. The taxonomy is applied to a number of exception handling models in some contemporary programming languages and some observations and conclusions offered.