Towards An Integrated Classification of Exceptions

Abstract: Exceptions refer to the situations that are not modelled by the system, or to deviations between what is planned and what really happens. In order to develop software systems which are more robust, thus delivering higher availability at a lower operating cost, the occurrence of exceptions needs to be reduced and the effects of the exceptions controlled. The number of exceptions arising during a software product’s execution is not an indication of its quality, since the execution depends on facts beyond the control of the software developer, such as, for example, the environment at execution time. The reaction of the product in response to the exceptions is, on the other hand, a definite measure of the quality. Errors that occur in programs, which result in exceptions being raised, are not all the same. A distinction should be made between the different types in order to categorize them and thus to be able to handle categories in a uniform way. This paper proposes a preliminary integrated classification which is derived from existing classifications