1. A computer-readable storage device, tangibly embodying a program of instructions executable by a machine to perform method steps for analyzing static source code of a computer program at static time, said method steps comprising: selecting the static source code of the computer program to be analyzed; selecting a class and method in the class based upon a selected class name from said selected static source code to be analyzed; generating a call tree as an ordered recursive sequence of all method calls in different classes or their instances that are invoked by said selected method in said selected class; generating a sequence diagram using said call tree by presenting the method calls as messages in the same order in which they appear in the call tree; and storing said sequence diagram, wherein the stored sequence diagram is used to analyze the effect of updates and changes made to the static source code of said computer program.