Return as hash code for the given object : Hash Code « Development Class « Java

Return as hash code for the given object

import java.lang.reflect.Array;
import java.util.Arrays;

 * Copyright 2002-2007 the original author or authors.
 * 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
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * See the License for the specific language governing permissions and
 * limitations under the License.

//Revised from springframework

 * Miscellaneous object utility methods. Mainly for internal use within the
 * framework; consider Jakarta's Commons Lang for a more comprehensive suite
 * of object utilities.
 * @author Juergen Hoeller
 * @author Keith Donald
 * @author Rod Johnson
 * @author Rob Harrop
 * @author Alex Ruiz
 * @since 19.03.2004
 * @see org.apache.commons.lang.ObjectUtils
abstract class ObjectUtils {

  private static final int INITIAL_HASH = 7;
  private static final int MULTIPLIER = 31;

  private static final String EMPTY_STRING = "";
  private static final String NULL_STRING = "null";
  private static final String ARRAY_START = "{";
  private static final String ARRAY_END = "}";
  private static final String EMPTY_ARRAY = ARRAY_START + ARRAY_END;
  private static final String ARRAY_ELEMENT_SEPARATOR = ", ";

   * Return as hash code for the given object; typically the value of
   * <code>{@link Object#hashCode()}</code>. If the object is an array,
   * this method will delegate to any of the <code>nullSafeHashCode</code>
   * methods for arrays in this class. If the object is <code>null</code>,
   * this method returns 0.
   * @see #nullSafeHashCode(Object[])
   * @see #nullSafeHashCode(boolean[])
   * @see #nullSafeHashCode(byte[])
   * @see #nullSafeHashCode(char[])
   * @see #nullSafeHashCode(double[])
   * @see #nullSafeHashCode(float[])
   * @see #nullSafeHashCode(int[])
   * @see #nullSafeHashCode(long[])
   * @see #nullSafeHashCode(short[])
  public static int nullSafeHashCode(Object obj) {
    if (obj == null) {
      return 0;
    if (obj instanceof Object[]) {
      return nullSafeHashCode((Object[]) obj);
    if (obj instanceof boolean[]) {
      return nullSafeHashCode((boolean[]) obj);
    if (obj instanceof byte[]) {
      return nullSafeHashCode((byte[]) obj);
    if (obj instanceof char[]) {
      return nullSafeHashCode((char[]) obj);
    if (obj instanceof double[]) {
      return nullSafeHashCode((double[]) obj);
    if (obj instanceof float[]) {
      return nullSafeHashCode((float[]) obj);
    if (obj instanceof int[]) {
      return nullSafeHashCode((int[]) obj);
    if (obj instanceof long[]) {
      return nullSafeHashCode((long[]) obj);
    if (obj instanceof short[]) {
      return nullSafeHashCode((short[]) obj);
    return obj.hashCode();



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