========================
Running Django on Jython
========================

.. index:: Jython, Java, JVM

Jython_ is an implementation of Python that runs on the Java platform (JVM).
This document will get you up and running with Django on top of Jython.

Installing Jython
=================

Django works with Jython versions 2.7b2 and higher. See the Jython_ website for
download and installation instructions.

.. _jython: http://www.jython.org/

Creating a servlet container
============================

If you just want to experiment with Django, skip ahead to the next section;
Django includes a lightweight Web server you can use for testing, so you won't
need to set up anything else until you're ready to deploy Django in production.

If you want to use Django on a production site, use a Java servlet container,
such as `Apache Tomcat`_. Full JavaEE applications servers such as `GlassFish`_
or `JBoss`_ are also OK, if you need the extra features they include.

.. _`Apache Tomcat`: https://tomcat.apache.org/
.. _GlassFish: https://javaee.github.io/glassfish/
.. _JBoss: https://www.jboss.org/

Installing Django
=================

The next step is to install Django itself. This is exactly the same as
installing Django on standard Python, so see
:ref:`removing-old-versions-of-django` and :ref:`install-django-code` for
instructions.

Installing Jython platform support libraries
============================================

The `django-jython`_ project contains database backends and management commands
for Django/Jython development. Note that the builtin Django backends won't work
on top of Jython.

.. _`django-jython`: https://github.com/beachmachine/django-jython

To install it, follow the `installation instructions`_ detailed on the project
website. Also, read the `database backends`_ documentation there.

.. _`installation instructions`: https://pythonhosted.org/django-jython/quickstart.html#install
.. _`database backends`: https://pythonhosted.org/django-jython/database-backends.html

Differences with Django on Jython
=================================

.. index:: JYTHONPATH

At this point, Django on Jython should behave nearly identically to Django
running on standard Python. However, are a few differences to keep in mind:

* Remember to use the ``jython`` command instead of ``python``. The
  documentation uses ``python`` for consistency, but if you're using Jython
  you'll want to mentally replace ``python`` with ``jython`` every time it
  occurs.

* Similarly, you'll need to use the ``JYTHONPATH`` environment variable
  instead of ``PYTHONPATH``.

* Any part of Django that requires `Pillow`_ will not work.

.. _Pillow: https://pillow.readthedocs.io/en/latest/
