The Coexistence of Sequence Diagrams and Collaboration Diagrams in Unified Modeling Language

The interactive diagrams (ID) in the unified modeling language (UML) is consisted of object and the relation between objects, depicts the interaction relation and includes the information transferred between objects. As two interactive diagrams, the semantics of sequence diagrams (SD) and collaboration diagrams (CD) are equivalence in the unified modeling language, both diagrams can be converted with each other without the lost of information. But it is necessary that both diagrams coexist in the unified modeling language because their emphases are different in the course of interaction. Such study is instructive for practitioners to select both diagrams in real tasks.