Added documentation for import_cleaner
diff --git a/java_gen/import_cleaner.py b/java_gen/import_cleaner.py
index 83897d4..d84d76b 100755
--- a/java_gen/import_cleaner.py
+++ b/java_gen/import_cleaner.py
@@ -1,4 +1,34 @@
-#!/usr/bin/python
+# Copyright 2013, Big Switch Networks, Inc.
+#
+# LoxiGen is licensed under the Eclipse Public License, version 1.0 (EPL), with
+# the following special exception:
+#
+# LOXI Exception
+#
+# As a special exception to the terms of the EPL, you may distribute libraries
+# generated by LoxiGen (LoxiGen Libraries) under the terms of your choice, provided
+# that copyright and licensing notices generated by LoxiGen are not altered or removed
+# from the LoxiGen Libraries and the notice provided below is (i) included in
+# the LoxiGen Libraries, if distributed in source code form and (ii) included in any
+# documentation for the LoxiGen Libraries, if distributed in binary form.
+#
+# Notice: "Copyright 2013, Big Switch Networks, Inc. This library was generated by the LoxiGen Compiler."
+#
+# You may not use this file except in compliance with the EPL or LOXI Exception. You may obtain
+# a copy of the EPL at:
+#
+# http://www.eclipse.org/legal/epl-v10.html
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# EPL for the specific language governing permissions and limitations
+# under the EPL.
+
+# A utility for naively cleaning of redundant 'import' statements in java source file.
+# This utility searches the name of the imported class in the code and if not found,
+# removes the corresponding import statement.
+# This utility assumes class/package naming that follows java naming conventions.
import sys
import re