Issue2302

$ wget https://bootstrap.pypa.io/get-pip.py
$ ~/local/jython2.7rc1/bin/jython get-pip.py
*sys-package-mgr*: processing new jar, '/private/var/folders/11/3pzjxxcd7q53dbfsm95ms3d00000gn/T/tmpjvJtfB/pip.zip'
Traceback (most recent call last):
  File "get-pip.py", line 20204, in <module>
    main()
  File "get-pip.py", line 152, in main
    bootstrap(tmpdir=tmpdir)
  File "get-pip.py", line 82, in bootstrap
    import pip
  File "/var/folders/11/3pzjxxcd7q53dbfsm95ms3d00000gn/T/tmpjvJtfB/pip.zip/pip/__init__.py", line 15, in <module>
  File "/var/folders/11/3pzjxxcd7q53dbfsm95ms3d00000gn/T/tmpjvJtfB/pip.zip/pip/vcs/subversion.py", line 9, in <module>
  File "/var/folders/11/3pzjxxcd7q53dbfsm95ms3d00000gn/T/tmpjvJtfB/pip.zip/pip/index.py", line 29, in <module>
  File "/var/folders/11/3pzjxxcd7q53dbfsm95ms3d00000gn/T/tmpjvJtfB/pip.zip/pip/_vendor/__init__.py", line 72, in load_module
  File "/var/folders/11/3pzjxxcd7q53dbfsm95ms3d00000gn/T/tmpjvJtfB/pip.zip/pip/_vendor/__init__.py", line 61, in load_module
  File "/var/folders/11/3pzjxxcd7q53dbfsm95ms3d00000gn/T/tmpjvJtfB/pip.zip/pip/_vendor/html5lib/__init__.py", line 16, in <module>
  File "/var/folders/11/3pzjxxcd7q53dbfsm95ms3d00000gn/T/tmpjvJtfB/pip.zip/pip/_vendor/html5lib/html5parser.py", line 6, in <module>
UnicodeDecodeError: 'unicodeescape' codec can't decode bytes in position 47-53: illegal Unicode character


It seems Jython can't decode some unicode literal in this file.
https://github.com/pypa/pip/blob/develop/pip/_vendor/html5lib/inputstream.py

This is a known issue with the html5lib vendor lib for pip, because it attempts to use isolated surrogate Unicode codepoints, and that's not legal for the UTF-16 used by Java/Jython.

You also reported #2301, so you're trying ensurepip. The other way to install the same pip we bundle with Jython is to install with setup.py directly from this fork: https://github.com/jythontools/pip

This has already been resolved upstream.