A process displays differences between design artifacts and object-oriented code. The process includes the step of displaying a first design artifact depicting an existing design of a first object, including an existing method and an existing collaboration relationship with a second object. The process continues by storing modified object oriented code representing a modified design of the first object, including a modified method. The process continues by displaying in a second design artifact, results of design virtual machine execution of the modified method. Then the process identifies a modified collaboration relationship with the second object by analyzing a modified message from the modified method to the second object. The process displays the modified collaboration relationship with the second object by juxtaposing at least portions of the first and second design artifacts. The modified collaboration relationship can be displayed as highlighted by different shades of gray or by different colors. The process can also display in the second design artifact, changes in attributes of the first object or changes between the existing method and the modified method of the first object. The design artifact can be displayed as a CRC report format, as an Object Structure Diagram format, or an Object Interaction Diagram format.