2 ABSTRACT Well-known CASE tools only generate the heading of the methods to automatically generate source code from UML diagrams. Some proposals partially generate the body of the methods; however they use non-standard modeling elements or hand-made source code elements. This paper proposes a process for generating the body of the methods from class diagram in an attempt to overcome such constraints. Semantics of class operations was thus defined as a way of linking class diagram o- perations to development platform implemented methods. These kinds of semantics use pre- and post-conditions belonging to the and the development platform library meta-model. This process is also exemplified by giving a case study. An UML instance of the java.sql package meta-model was created for developing the case study.