Because software is everywhere and has continued to play a major part in our daily lives, software piracy and plagiarism are still rampant. The tools has been developed and used in order to detect pirated copies of software at source code level. JPlag, MOSS, and exEyes are well-known source code plagiarism detectors. In this paper, we explain briefly different types of classical code clones, and compare the performance of JPlag and exEyes using Java source code files. The performance comparison between JPlag and exEyes are conducted using a benchmark, BigCloneBench which is a big benchmark of real clones. We evaluate the performance of the tools measuring their precision, recall, and F-measure.
Experimental results show that both precision and recall rates of the two tools become 100% for simple type-1 and 2 clones. For more complicated type-3 clones, however, JPlag and exEyes have a precision rate of 95% and 100%, and a recall rate of 50.1% and 27.7% respectively.