Defining contracts with different tools in software development

Abstract. To create reliable software systems, different tools and methods are needed. To analyse the available tools and methods, two main software development levels were chosen. The first is the model (UML with OCL, ADL, JML) level. This is important because with models different checks can be made, which can help to find software failures earlier. However, the checks at the model level are not enough. Analysis was also made on the second, implementation level (Eiffel, Java, .NET), where the programming language extensions for contract based development were examined.