Jython is an implementation of the high-level, dynamic, object-oriented language Python written in 100% Pure Java, and seamlessly integrated with the Java platform. It thus allows you to run Python on any Java platform.

Apache TinkerPop :: Gremlin Python

Turbine is a servlet based framework that allows experienced Java developers to quickly build secure web applications. Parts of Turbine can also be used independently of the web portion of Turbine as well.

Zeppelin interpreter for Apache Pig

cas-server-support-script-engines

Javadoc Doclet that uses Pygments for code highlighting.

E Governments ERP EAR

eGov opensource ERP solution for municipal e-governance

The Python language plugin allows to have python as the language of scripts to execute.

Elasticsearch project

Okapi Camunda module for Business Process Management