Fixed #20016: worked around Jython not having a buffer.

django/utils/six.py

@@ -414,8 +414,12 @@ else:
     _assertRaisesRegex = "assertRaisesRegexp"
     _assertRegex = "assertRegexpMatches"
     # memoryview and buffer are not stricly equivalent, but should be fine for
-    # django core usage (mainly BinaryField)
-    memoryview = buffer
+    # django core usage (mainly BinaryField). However, Jython doesn't support
+    # buffer (see http://bugs.jython.org/issue1521), so we have to be careful.
+    if sys.platform.startswith('java'):
+        memoryview = memoryview
+    else:
+        memoryview = buffer
 
 
 def assertRaisesRegex(self, *args, **kwargs):