Java String remove character set from end

//package com.demo2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        String str = "";
        String stripChars = "";
        System.out.println(stripEnd(str, stripChars));
    }/*from www .j a  v a2  s. c om*/
    /**
     * <p>Strips any of a set of characters from the end of a String.</p>
     *
     * <p>A <code>null</code> input String returns <code>null</code>.
     * An empty string ("") input returns the empty string.</p>
     *
     * <p>If the stripChars String is <code>null</code>, whitespace is
     * stripped as defined by {@link Character#isWhitespace(char)}.</p>
     *
     * <pre>
     * stripEnd(null, *)          = null
     * stripEnd("", *)            = ""
     * stripEnd("abc", "")        = "abc"
     * stripEnd("abc", null)      = "abc"
     * stripEnd("  abc", null)    = "  abc"
     * stripEnd("abc  ", null)    = "abc"
     * stripEnd(" abc ", null)    = " abc"
     * stripEnd("  abcyx", "xyz") = "  abc"
     * </pre>
     *
     * @param str  the String to remove characters from, may be null
     * @param stripChars  the characters to remove, null treated as whitespace
     * @return the stripped String, <code>null</code> if null String input
     */
    public static String stripEnd(String str, String stripChars) {
        int end;
        if (str == null || (end = str.length()) == 0) {
            return str;
        }

        if (stripChars == null) {
            while ((end != 0) && Character.isWhitespace(str.charAt(end - 1))) {
                end--;
            }
        } else if (stripChars.length() == 0) {
            return str;
        } else {
            while ((end != 0) && (stripChars.indexOf(str.charAt(end - 1)) != -1)) {
                end--;
            }
        }
        return str.substring(0, end);
    }
    
}
  
/*
 * Licensed 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.
 */