Japanese is here.
Abstract We propose an idea of identifying a point in a program execution trace by a pair of ``line number in source files'' and a counter, ``timestamp''. The counter increases when a control point in a program jumps such as function calls and loops. We call the point in a trace ``position'' and apply it to the execution control of programs for debugging, and so on. We implemented the timestamp system for Java programs. Transforming Java class files, we inserted bytecodes for updating timestamp just before the control point jumps. In this paper, we describe the applications and the implementation details of ``position''. Overhead measurement of added codes is also included.