Finish properly hiding importlib implementation code.
diff --git a/Lib/importlib/NOTES b/Lib/importlib/NOTES
index 2c76fc4..2220a16 100644
--- a/Lib/importlib/NOTES
+++ b/Lib/importlib/NOTES
@@ -7,15 +7,6 @@
 
     + Expose function to see if a frozen module is a package.
 
-* Remove ``import *`` from importlib.__init__.
-
-* Remove __all__ from importlib._bootstrap.
-
-* Add leading underscores to all objects in importlib._bootstrap that are not
-  publicly exposed.
-
-* Reorder importlib/_bootstrap.py so definitions are not in inverted order.
-
 * Make sure that there is documentation *somewhere* fully explaining the
 semantics of import that can be referenced from the package's documentation
 (even if it is in the package documentation itself, although it might be best
diff --git a/Lib/importlib/__init__.py b/Lib/importlib/__init__.py
index 2f93621..7474350 100644
--- a/Lib/importlib/__init__.py
+++ b/Lib/importlib/__init__.py
@@ -136,7 +136,3 @@
                 break
             level += 1
     return _bootstrap._gcd_import(name[level:], package, level)
-
-
-# XXX This should go away once the public API is done.
-from ._bootstrap import *
diff --git a/Lib/importlib/_bootstrap.py b/Lib/importlib/_bootstrap.py
index c5588e0..5e9e16e 100644
--- a/Lib/importlib/_bootstrap.py
+++ b/Lib/importlib/_bootstrap.py
@@ -387,7 +387,7 @@
         return code_object
 
 
-class PyFileLoader(PyLoader):
+class _PyFileLoader(PyLoader):
 
     """Load a Python source file."""
 
@@ -452,7 +452,7 @@
         return self._is_pkg
 
 
-class PyPycFileLoader(PyPycLoader, PyFileLoader):
+class _PyPycFileLoader(PyPycLoader, _PyFileLoader):
 
     """Load a module from a source or bytecode file."""
 
@@ -626,7 +626,7 @@
             return None
 
 
-class FileFinder:
+class _FileFinder:
 
     """Base class for file finders.
 
@@ -685,12 +685,12 @@
             return None
 
 
-class PyFileFinder(FileFinder):
+class _PyFileFinder(_FileFinder):
 
     """Importer for source/bytecode files."""
 
     _possible_package = True
-    _loader = PyFileLoader
+    _loader = _PyFileLoader
 
     def __init__(self, path_entry):
         # Lack of imp during class creation means _suffixes is set here.
@@ -700,11 +700,11 @@
         super().__init__(path_entry)
 
 
-class PyPycFileFinder(PyFileFinder):
+class _PyPycFileFinder(_PyFileFinder):
 
     """Finder for source and bytecode files."""
 
-    _loader = PyPycFileLoader
+    _loader = _PyPycFileLoader
 
     def __init__(self, path_entry):
         super().__init__(path_entry)
@@ -713,7 +713,7 @@
 
 
 
-class ExtensionFileFinder(FileFinder):
+class _ExtensionFileFinder(_FileFinder):
 
     """Importer for extension files."""
 
@@ -750,7 +750,7 @@
     return path_hook
 
 
-_DEFAULT_PATH_HOOK = _chained_path_hook(ExtensionFileFinder, PyPycFileFinder)
+_DEFAULT_PATH_HOOK = _chained_path_hook(_ExtensionFileFinder, _PyPycFileFinder)
 
 class _DefaultPathFinder(PathFinder):
 
@@ -902,8 +902,3 @@
                 except ImportError:
                     pass
         return module
-
-
-# XXX Eventually replace with a proper __all__ value (i.e., don't expose os
-# replacements but do expose _ExtensionFileLoader, etc. for testing).
-__all__ = [obj for obj in globals().keys() if not obj.startswith('__')]
diff --git a/Lib/importlib/test/extension/test_case_sensitivity.py b/Lib/importlib/test/extension/test_case_sensitivity.py
index 3387e70..2ccec89 100644
--- a/Lib/importlib/test/extension/test_case_sensitivity.py
+++ b/Lib/importlib/test/extension/test_case_sensitivity.py
@@ -1,7 +1,7 @@
 import sys
 from test import support
 import unittest
-import importlib
+from importlib import _bootstrap
 from .. import util
 from . import util as ext_util
 
@@ -13,7 +13,7 @@
         good_name = ext_util.NAME
         bad_name = good_name.upper()
         assert good_name != bad_name
-        finder = importlib.ExtensionFileFinder(ext_util.PATH)
+        finder = _bootstrap._ExtensionFileFinder(ext_util.PATH)
         return finder.find_module(bad_name)
 
     def test_case_sensitive(self):
diff --git a/Lib/importlib/test/extension/test_finder.py b/Lib/importlib/test/extension/test_finder.py
index 3fc9b0b..39e26a7 100644
--- a/Lib/importlib/test/extension/test_finder.py
+++ b/Lib/importlib/test/extension/test_finder.py
@@ -1,4 +1,4 @@
-import importlib
+from importlib import _bootstrap
 from .. import abc
 from . import util
 
@@ -9,7 +9,7 @@
     """Test the finder for extension modules."""
 
     def find_module(self, fullname):
-        importer = importlib.ExtensionFileFinder(util.PATH)
+        importer = _bootstrap._ExtensionFileFinder(util.PATH)
         return importer.find_module(fullname)
 
     def test_module(self):
diff --git a/Lib/importlib/test/extension/test_loader.py b/Lib/importlib/test/extension/test_loader.py
index f961a63..157a3b6 100644
--- a/Lib/importlib/test/extension/test_loader.py
+++ b/Lib/importlib/test/extension/test_loader.py
@@ -1,4 +1,4 @@
-import importlib
+from importlib import _bootstrap
 from . import util as ext_util
 from .. import abc
 from .. import util
@@ -12,7 +12,7 @@
     """Test load_module() for extension modules."""
 
     def load_module(self, fullname):
-        loader = importlib._ExtensionFileLoader(ext_util.NAME,
+        loader = _bootstrap._ExtensionFileLoader(ext_util.NAME,
                                                 ext_util.FILEPATH, False)
         return loader.load_module(fullname)
 
@@ -25,7 +25,7 @@
                 self.assertEqual(getattr(module, attr), value)
             self.assert_(ext_util.NAME in sys.modules)
             self.assert_(isinstance(module.__loader__,
-                                    importlib._ExtensionFileLoader))
+                                    _bootstrap._ExtensionFileLoader))
 
     def test_package(self):
         # Extensions are not found in packages.
diff --git a/Lib/importlib/test/extension/test_path_hook.py b/Lib/importlib/test/extension/test_path_hook.py
index 76f4995..8532956 100644
--- a/Lib/importlib/test/extension/test_path_hook.py
+++ b/Lib/importlib/test/extension/test_path_hook.py
@@ -1,4 +1,4 @@
-import importlib
+from importlib import _bootstrap
 from . import util
 
 import collections
@@ -14,7 +14,7 @@
     # XXX Should it only work for directories containing an extension module?
 
     def hook(self, entry):
-        return importlib.ExtensionFileFinder(entry)
+        return _bootstrap._ExtensionFileFinder(entry)
 
     def test_success(self):
         # Path hook should handle a directory where a known extension module
diff --git a/Lib/importlib/test/source/test_case_sensitivity.py b/Lib/importlib/test/source/test_case_sensitivity.py
index 210e620..368e893 100644
--- a/Lib/importlib/test/source/test_case_sensitivity.py
+++ b/Lib/importlib/test/source/test_case_sensitivity.py
@@ -1,5 +1,5 @@
 """Test case-sensitivity (PEP 235)."""
-import importlib
+from importlib import _bootstrap
 from .. import util
 from . import util as source_util
 import os
@@ -19,7 +19,7 @@
     assert name != name.lower()
 
     def find(self, path):
-        finder = importlib.PyPycFileFinder(path)
+        finder = _bootstrap._PyPycFileFinder(path)
         return finder.find_module(self.name)
 
     def sensitivity_test(self):
diff --git a/Lib/importlib/test/source/test_file_loader.py b/Lib/importlib/test/source/test_file_loader.py
index 3da4426..f3d75c3 100644
--- a/Lib/importlib/test/source/test_file_loader.py
+++ b/Lib/importlib/test/source/test_file_loader.py
@@ -1,4 +1,5 @@
 import importlib
+from importlib import _bootstrap
 from .. import abc
 from . import util as source_util
 
@@ -19,7 +20,8 @@
     # [basic]
     def test_module(self):
         with source_util.create_modules('_temp') as mapping:
-            loader = importlib.PyPycFileLoader('_temp', mapping['_temp'], False)
+            loader = _bootstrap._PyPycFileLoader('_temp', mapping['_temp'],
+                                                    False)
             module = loader.load_module('_temp')
             self.assert_('_temp' in sys.modules)
             check = {'__name__': '_temp', '__file__': mapping['_temp'],
@@ -29,8 +31,9 @@
 
     def test_package(self):
         with source_util.create_modules('_pkg.__init__') as mapping:
-            loader = importlib.PyPycFileLoader('_pkg', mapping['_pkg.__init__'],
-                                             True)
+            loader = _bootstrap._PyPycFileLoader('_pkg',
+                                                 mapping['_pkg.__init__'],
+                                                 True)
             module = loader.load_module('_pkg')
             self.assert_('_pkg' in sys.modules)
             check = {'__name__': '_pkg', '__file__': mapping['_pkg.__init__'],
@@ -42,8 +45,8 @@
 
     def test_lacking_parent(self):
         with source_util.create_modules('_pkg.__init__', '_pkg.mod')as mapping:
-            loader = importlib.PyPycFileLoader('_pkg.mod', mapping['_pkg.mod'],
-                                             False)
+            loader = _bootstrap._PyPycFileLoader('_pkg.mod',
+                                                    mapping['_pkg.mod'], False)
             module = loader.load_module('_pkg.mod')
             self.assert_('_pkg.mod' in sys.modules)
             check = {'__name__': '_pkg.mod', '__file__': mapping['_pkg.mod'],
@@ -57,7 +60,8 @@
 
     def test_module_reuse(self):
         with source_util.create_modules('_temp') as mapping:
-            loader = importlib.PyPycFileLoader('_temp', mapping['_temp'], False)
+            loader = _bootstrap._PyPycFileLoader('_temp', mapping['_temp'],
+                                                    False)
             module = loader.load_module('_temp')
             module_id = id(module)
             module_dict_id = id(module.__dict__)
@@ -87,7 +91,8 @@
                 setattr(orig_module, attr, value)
             with open(mapping[name], 'w') as file:
                 file.write('+++ bad syntax +++')
-            loader = importlib.PyPycFileLoader('_temp', mapping['_temp'], False)
+            loader = _bootstrap._PyPycFileLoader('_temp', mapping['_temp'],
+                                                    False)
             self.assertRaises(SyntaxError, loader.load_module, name)
             for attr in attributes:
                 self.assertEqual(getattr(orig_module, attr), value)
@@ -97,7 +102,8 @@
         with source_util.create_modules('_temp') as mapping:
             with open(mapping['_temp'], 'w') as file:
                 file.write('=')
-            loader = importlib.PyPycFileLoader('_temp', mapping['_temp'], False)
+            loader = _bootstrap._PyPycFileLoader('_temp', mapping['_temp'],
+                                                    False)
             self.assertRaises(SyntaxError, loader.load_module, '_temp')
             self.assert_('_temp' not in sys.modules)
 
@@ -116,7 +122,7 @@
     """
 
     def import_(self, file, module_name):
-        loader = importlib.PyPycFileLoader(module_name, file, False)
+        loader = _bootstrap._PyPycFileLoader(module_name, file, False)
         module = loader.load_module(module_name)
         self.assert_(module_name in sys.modules)
 
diff --git a/Lib/importlib/test/source/test_finder.py b/Lib/importlib/test/source/test_finder.py
index 1e4333c..dd56429 100644
--- a/Lib/importlib/test/source/test_finder.py
+++ b/Lib/importlib/test/source/test_finder.py
@@ -1,4 +1,4 @@
-import importlib
+from importlib import _bootstrap
 from .. import abc
 from . import util as source_util
 import os
@@ -32,7 +32,7 @@
     """
 
     def import_(self, root, module):
-        finder = importlib.PyPycFileFinder(root)
+        finder = _bootstrap._PyPycFileFinder(root)
         return finder.find_module(module)
 
     def run_test(self, test, create=None, *, compile_=None, unlink=None):
diff --git a/Lib/importlib/test/source/test_path_hook.py b/Lib/importlib/test/source/test_path_hook.py
index 9a4ccbe..71ca508 100644
--- a/Lib/importlib/test/source/test_path_hook.py
+++ b/Lib/importlib/test/source/test_path_hook.py
@@ -1,4 +1,4 @@
-import importlib
+from importlib import _bootstrap
 from . import util as source_util
 import unittest
 
@@ -10,7 +10,7 @@
     def test_success(self):
         # XXX Only work on existing directories?
         with source_util.create_modules('dummy') as mapping:
-            self.assert_(hasattr(importlib.FileFinder(mapping['.root']),
+            self.assert_(hasattr(_bootstrap._FileFinder(mapping['.root']),
                                  'find_module'))
 
 
diff --git a/Lib/importlib/test/source/test_source_encoding.py b/Lib/importlib/test/source/test_source_encoding.py
index 9e9c7e8..3734712 100644
--- a/Lib/importlib/test/source/test_source_encoding.py
+++ b/Lib/importlib/test/source/test_source_encoding.py
@@ -1,4 +1,4 @@
-import importlib
+from importlib import _bootstrap
 from . import util as source_util
 
 import codecs
@@ -35,7 +35,7 @@
         with source_util.create_modules(self.module_name) as mapping:
             with open(mapping[self.module_name], 'wb')as file:
                 file.write(source)
-            loader = importlib.PyPycFileLoader(self.module_name,
+            loader = _bootstrap._PyPycFileLoader(self.module_name,
                                        mapping[self.module_name], False)
             return loader.load_module(self.module_name)
 
@@ -96,8 +96,8 @@
         with source_util.create_modules(module_name) as mapping:
             with open(mapping[module_name], 'wb') as file:
                 file.write(source)
-            loader = importlib.PyPycFileLoader(module_name, mapping[module_name],
-                                                False)
+            loader = _bootstrap._PyPycFileLoader(module_name,
+                                                 mapping[module_name], False)
             return loader.load_module(module_name)
 
     # [cr]