How can I install various Python libraries in Jython?

Some Python modules, like lxml, have required components in C. These won't work in Jython.

Most Python packages will work fine, and you can install them using the same tools as you use in CPython. This is described in Appendix A of Jython Book:

To get setuptools, download ez_setup.py from http://peak.telecommunity.com/dist/ez_setup.py. Then, go to the directory where you left the downloaded file and execute:

$ jython ez_setup.py

[The easy_install script will be] installed to the bin directory of the Jython installation (/home/lsoto/jython2.5.0/bin in the example above). If you work frequently with Jython, it’s a good idea to prepend this directory to the PATH environment variable, so you don’t have to type the whole path each time you want to use easy_install or other scripts installed to this directory.

Testing it myself, after installing setuptools in Jython, pip installed correctly:

$ sudo /usr/bin/jython2.5.2b1/bin/easy_install pipSearching for pip[...]Installing pip-2.5 script to /usr/bin/jython2.5.2b1/binInstalling pip script to /usr/bin/jython2.5.2b1/binInstalled /usr/bin/jython2.5.2b1/Lib/site-packages/pip-1.0.2-py2.5.eggProcessing dependencies for pipFinished processing dependencies for pip$ sudo /usr/bin/jython2.5.2b1/bin/pip install bottleDownloading/unpacking bottle  Downloading bottle-0.9.6.tar.gz (45Kb): 45Kb downloaded  Running setup.py egg_info for package bottle    Installing collected packages: bottle  Running setup.py install for bottleSuccessfully installed bottleCleaning up...$ jythonJython 2.5.2b1 (Release_2_5_2beta1:7075, Jun 28 2010, 07:44:20) [Java HotSpot(TM) 64-Bit Server VM (Apple Inc.)] on java1.6.0_26Type "help", "copyright", "credits" or "license" for more information.>>> import bottle>>> bottle<module 'bottle' from '/usr/bin/jython2.5.2b1/Lib/site-packages/bottle$py.class'>>>>

As of v2.7b4, the Jython distribution includes the ensurepip module, which simplifies installation of pip and setuptools:

jython -m ensurepip

Beware of sys.platform=='win32' issue that will get in your way of using PyPI packages which relying on this method to determine host platform.

Being Jython though you have the power of the Java libraries, not the limitation of being unable to install a few python C libraries.

For example you would be better using Jsoup instead of Beautiful soup or go for a full solution like Jtidy.

Use Jaxp instead of lxml.

Also another option that fits your reuirements is NekoHTML