1. Apache Lucene. https://lucene.apache.org/. Apache Lucene. https://lucene.apache.org/.
2. IBM CPLEX Optimizer. http://www.ibm.com/software/commerce/ optimization/cplex-optimizer/. IBM CPLEX Optimizer. http://www.ibm.com/software/commerce/ optimization/cplex-optimizer/.
3. Javalanche. http://javalanche.org/. Javalanche. http://javalanche.org/.
4. Maven. http://maven.apache.org/. Maven. http://maven.apache.org/.
5. PIT mutation testing. http://pitest.org/. PIT mutation testing. http://pitest.org/.