Skip to content


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?

Latest commit


Git stats


Failed to load latest commit information.
Latest commit message
Commit time

JaRFly: Java Repair Framework


A more detailed user manual for JaRFly is located at


JarFly is in active development and changes often.

What is this repository for?

This repository contains JaRFly, a Java Repair Framework for implementing automated repair tools for Java programs, such as GenProg, Par, TrpAutoRepair, and so on. The project is called GenProg4Java because, originally, it only implemented the GenProg algorithm, but today, it is an entire framework for many algorithms.

You can read more about GenProg and program repair here:

Running JaRFly

At a high level, JaRFly takes as input a program with a bug and test cases. At least one test case should be failing; it encodes the bug to be repaired. At least one should be passing; it encodes desired functionality that should be maintained.

At the sea level, JaRFly takes a configuration file as input. Below, we provide a minimal set that should allow JaRFly to run using the default genetic programming heuristic on a buggy program taken from the IntroClassJava dataset ( There are other options available. The comments below are explanatory; they may not work in actual config files. You can see the avaialble flags and their defaults, when applicable in ( However, to illustrate:

javaVM = /usr/bin/java 
classTestFolder = bin/ # where to find test classes
workingDir = /path/to/IntroClassJava/dataset/median/testmedian/000/ #top level directory
outputDir = /path/to/IntroClassJava/dataset/median/testmedian/000/tmp/ #where temporary files should be stored
libs=/path/to/genprog4java/lib/hamcrest-core-1.3.jar:/path/to/genprog4java/lib/junit-4.12.jar:/path/to/genprog4java/lib/junittestrunner.jar: # to run the program under repair
sourceDir = src/main/java # relative to workingDir; path to top of package-level source for class under repair
positiveTests = /path/to/IntroClassJava/dataset/median/testmedian/000/pos.tests # file listing test classes or methods that should initially pass, one per line
negativeTests = /path/to/IntroClassJava/dataset/median/testmedian/000/neg.tests # file listing test classes or methods that should initially fail, one per line
jacocoPath = /path/to/genprog4java/lib/jacocoagent.jar # path to jacoco; g4j ships with a jar that should work
testClassPath=/path/to/IntroClassJava/dataset/median/testmedian/000/bin/ #classpath for tests, possibly redundant with classTestFolder, I should check
targetClassName = introclassJava.median_d4aae191_000 # class under repair, or file listing classes under repair, one per line

Although the other options are optional, you probably want to set a large number of them, such as the seed.

Individual classes also have individual configure methods; you can search for them to find more options. We are working on creating a common place that lists them.

In addition to the configuration file, you should specify to the VM; my VM arguments in my run configuration in Eclipse looks like:

-ea -Dlog4j.configuration=file:${workspace_loc:GenProg4Java}/src/

I also set the working directory to be the base directory for the project I'm trying to repair. Thus, for the Hello, World! example, the Working Directory is set as:


Hello, World!

genprog4java/tests/mathTest serves as a reasonable Hello, World! example. It has a miniTestConfiguration that should have flags close to what is necessary to get it to run, though we do change this file with some regularity so if it doesn't work out of the gate, double check that it doesn't look completely wacky.



Whom do I talk to?

Repo owner or admin