missing license

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1895019 13f79535-47bb-0310-9956-ffa450edef68

poi/src/main/java/org/apache/poi/util/RandomSingleton.java

@@ -1,3 +1,19 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   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 License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
 package org.apache.poi.util;
 
 import java.security.SecureRandom;