Trim off trailing blanks but not leading blanks in Java

//  ww  w.  jav a2s . c  om
public class Main {
  public static void main(String[] argv) {
    System.out.println(trimTrailing("   this is a test from java2s.com   "));
  }

  /**
   * Trim off trailing blanks but not leading blanks
   * 
   * @param str
   * 
   * @return The input with trailing blanks stipped off
   */
  public static String trimTrailing(String str) {
    if (str == null)
      return null;
    int len = str.length();
    for (; len > 0; len--) {
      if (!Character.isWhitespace(str.charAt(len - 1)))
        break;
    }
    return str.substring(0, len);
  } // end of trimTrailing

}
/*
 * 
 * Derby - Class org.apache.derby.iapi.util.PropertyUtil
 * 
 * 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.
 */