Java String remove character set from start

public class Main {
    public static void main(String[] argv) throws Exception {
        String str = "";
        String stripChars = "";
        System.out.println(stripStart(str, stripChars));
    }// w w w. j  a  v  a 2  s.co  m
    public static final String EMPTY = "";

    /**
     * <p>Strips any of a set of characters from the start 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>
     * stripStart(null, *)          = null
     * stripStart("", *)            = ""
     * stripStart("abc", "")        = "abc"
     * stripStart("abc", null)      = "abc"
     * stripStart("  abc", null)    = "abc"
     * stripStart("abc  ", null)    = "abc  "
     * stripStart(" abc ", null)    = "abc "
     * stripStart("yxabc  ", "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 stripStart(String str, String stripChars) {
        int strLen;
        if (str == null || (strLen = str.length()) == 0) {
            return str;
        }
        int start = 0;
        if (stripChars == null) {
            while ((start != strLen) && Character.isWhitespace(str.charAt(start))) {
                start++;
            }
        } else if (stripChars.length() == 0) {
            return str;
        } else {
            while ((start != strLen) && (stripChars.indexOf(str.charAt(start)) != -1)) {
                start++;
            }
        }
        return str.substring(start);
    }

    
}
/*
 * 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.
 */