What is JPlag

JPlag is a system that finds similarities among multiple sets of source code files. This way it can detect software plagiarism. JPlag does not merely compare bytes of text, but is aware of programming language syntax and program structure and hence is robust against many kinds of attempts to disguise similarities between plagiarized files. JPlag currently supports Java, C#, C, C++, Scheme, and natural language text.
JPlag is typically used to detect and thus discourage the unallowed copying of student exercise programs in programming education. But in principle it can also be used to detect stolen software parts among large amounts of source text or modules that have been duplicated (and only slightly modified). JPlag has already played a part in several intellectual property cases where it has been successfully used by expert witnesses.
JPlag has a powerful graphical interface for presenting its results. See our

Getting a Jplag account

The use of JPlag is free, but you must obtain an account. This requirement is not only necessary to avoid unauthorized use of JPlag by students, but also to provide the easy and installation-free access to the software.
For obtaining a JPlag account, please contact the authors by e-mail at JPlag@ira.uka.de and shortly describe the purpose for which you want to use JPlag (which university/school and course etc.). Please note that we do not give accounts to users of anonymous email address like Hotmail, Yahoo, Gmail, etc.
Just to make it clear: Currently JPlag does not compare to the internet! It is designed to find similarities among the student solutions, which is usually sufficient for computer programs.

Installing and starting JPlag Client

This JPlag Client is a java webstart based application. Since you have a JPlag account, you only need to have a suitable java web start version installed in your computer. For that purpose, make sure that you have Java Runtime Environement with version 1.4.2 or higher installed in your Computer or download java 2 standart edition 5.0 ,which contains a suitable Java web start version.
When starting the Jplag web start Client for the first time, a dialog will appears and you will have to make some basic settings.

Setting username and password.

Please enter the username and the password in the specified Fields. Read more about changing your password here. Note that your username and password will be saved in your computer.If you don“t trust your environement, then do not save your password. In that case, you will have to enter it every time, when starting JPlag.

Setting JPlag home directory.

Your JPlag home directory is the default directory where your JPlag results are stored ,and is used by JPlag Client to store temporar files.

Setting country language.

JPlag is a international oriented application, and the JPlag results are available in many languages. We are also trying to make this JPlag client available in as many language as possible. Maybe you help us doing it. The currently supported country languages are Englisch, French , German and Portuguese .
Copyright © 1996-2005 JPlag team University of Karlsruhe.