Index: setuptools/tests/test_resources.py
===================================================================
--- setuptools/tests/test_resources.py	(revision 66050)
+++ setuptools/tests/test_resources.py	(working copy)
@@ -1,6 +1,11 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+# NOTE: the shebang line is for ScriptHeaderTests
 from unittest import TestCase, makeSuite
 from pkg_resources import *
-import pkg_resources, sys
+from setuptools.command.easy_install import get_script_header, is_sh
+import os, pkg_resources, sys
+from StringIO import StringIO
 try:
     frozenset
 except NameError:
@@ -491,3 +496,48 @@
 
 
 
+class ScriptHeaderTests(TestCase):
+
+    non_ascii_exe = '/Users/José/bin/python'
+
+    def test_get_script_header(self):
+        if sys.platform.startswith('java') and is_sh(sys.executable):
+            # Tested below
+            return
+
+        self.assertEqual(get_script_header('#!/usr/local/bin/python'),
+                         '#!%s\n' % os.path.normpath(sys.executable))
+        self.assertEqual(get_script_header('#!/usr/bin/python -x'),
+                         '#!%s  -x\n' % os.path.normpath(sys.executable))
+        self.assertEqual(get_script_header('#!/usr/bin/python',
+                                           executable=self.non_ascii_exe),
+                         '#!%s -x\n' % self.non_ascii_exe)
+
+    def test_get_script_header_jython_workaround(self):
+        platform = sys.platform
+        sys.platform = 'java1.5.0_13'
+        stderr = sys.stderr
+        try:
+            # A mock sys.executable that uses a shebang line (this file)
+            exe = os.path.normpath(os.path.splitext(__file__)[0] + '.py')
+
+            self.assertEqual(get_script_header('#!/usr/local/bin/python',
+                                               executable=exe),
+                             '#!/usr/bin/env %s\n' % exe)
+
+            # Ensure we generate what is basically a broken shebang line
+            # when there's options, with a warning emitted
+            sys.stderr = StringIO()
+            self.assertEqual(get_script_header('#!/usr/bin/python -x',
+                                               executable=exe),
+                             '#!%s  -x\n' % exe)
+            self.assert_('Unable to adapt shebang line' in sys.stderr.getvalue())
+
+            sys.stderr = StringIO()
+            self.assertEqual(get_script_header('#!/usr/bin/python',
+                                               executable=self.non_ascii_exe),
+                             '#!%s -x\n' % self.non_ascii_exe)
+            self.assert_('Unable to adapt shebang line' in sys.stderr.getvalue())
+        finally:
+            sys.platform = platform
+            sys.stderr = stderr
Index: setuptools/command/easy_install.py
===================================================================
--- setuptools/command/easy_install.py	(revision 66050)
+++ setuptools/command/easy_install.py	(working copy)
@@ -1421,8 +1421,11 @@
         executable = "python.exe"
     else:
         executable = nt_quote_arg(executable)
+
     hdr = "#!%(executable)s%(options)s\n" % locals()
-    if unicode(hdr,'ascii','ignore').encode('ascii') != hdr:
+    non_ascii_hdr = unicode(hdr,'ascii','ignore').encode('ascii') != hdr
+
+    if non_ascii_hdr:
         # Non-ascii path to sys.executable, use -x to prevent warnings
         if options:
             if options.strip().startswith('-'):
@@ -1430,7 +1433,20 @@
             # else: punt, we can't do it, let the warning happen anyway
         else:
             options = ' -x'
-        hdr = "#!%(executable)s%(options)s\n" % locals()
+
+    if sys.platform.startswith('java') and is_sh(executable):
+        # Workaround Jython's sys.executable being a .sh (an invalid
+        # shebang line interpreter)
+        if options:
+            # Can't apply the workaround, leave it broken
+            print >> sys.stderr, \
+                ("WARNING: Unable to adapt shebang line for Jython, "
+                 "the following script is NOT executable\n         see "
+                 "http://bugs.jython.org/issue1112 for more information.")
+        else:
+            executable = '/usr/bin/env %s' % executable
+
+    hdr = "#!%(executable)s%(options)s\n" % locals()
     return hdr
 
 def auto_chmod(func, arg, exc):
@@ -1637,6 +1653,17 @@
     import setuptools; argv0 = os.path.dirname(setuptools.__path__[0])
     sys.argv[0] = argv0; sys.argv.append(argv0); main()
 
+def is_sh(executable):
+    """Determine if the specified executable is a .sh (contains a
+    shebang line)
+    """
+    try:
+        fp = open(executable)
+        magic = fp.read(2)
+        fp.close()
+    except (OSError,IOError):
+        return executable
+    return magic == '#!'
 
 def main(argv=None, **kw):
     from setuptools import setup