Open Systems Laboratory at Illinois


The Java Concolic Unit Testing Engine (jCUTE) automatically generates unit tests for Java programs. Concolic execution combines randomized concrete execution with symbolic execution and automatic constraint solving. Symbolic execution allows jCUTE to discern inputs that lead down different execution paths; randomized concrete execution helps it overcome limitations of the constraint solver, like the inability to analyze system calls or solve general systems of non-linear integer equations. Through this combination, jCUTE is able to generate test cases that execute many different execution paths in real Java programs.

jCUTE supports multi-threaded programs. It can discover race conditions and deadlocks through systematic schedule exploration.




jCUTE requires an installed and working Java Development Kit (JDK) version 1.4 or later. To run jCUTE on a 32-bit system, download and unzip the binary distribution.

  • On Linux, run the setup script. Then execute the jcutegui script.
  • On Windows, run the jcutegui.bat batch file.

Compiling the Constraint Solving Library on Linux

jCUTE uses the lp_solve linear programming library for constraint solving. It comes with pre-compiled 32-bit versions of this C library, which it accesses via the Java Native Interface (JNI). However, the library and the wrapper were compiled against old standard libraries ( that are no longer available on modern Linux systems. A potential solution for this is to install an old 32-bit Linux image into a virtual machine for running jCUTE in it. Another solution is to compile the libraries on one's system. The README file contains instructions for compiling lp_solve and its JNI wrapper.

64-bit Systems

The lp_solve library compiles and appears to work fine on 64-bit systems.


The jCUTE software is NOT in the public domain. However, it is freely available without fee for education, research, and non-profit purposes as described in the complete jCUTE license. The third-party libraries used by jCUTE are licensed as described in their license files.


jCUTE was designed and implemented by Koushik Sen around 2006.