java.long.object类中的重要方法

//String类中对equals方法的重写

public boolean equals(Object anObject) {
 2         if (this == anObject) {
 3             return true;
 4         }
 5         if (anObject instanceof String) {
 6             String anotherString = (String) anObject;
 7             int n = value.length;
 8             if (n == anotherString.value.length) {
 9                 char v1[] = value;
10                 char v2[] = anotherString.value;
11                 int i = 0;
12                 while (n-- != 0) {
13                     if (v1[i] != v2[i])
14                             return false;
15                     i++;
16                 }
17                 return true;
18             }
19         }
20         return false;
21     }

//String类中对hashcode()方法的重写

public int hashCode() {
 2     int h = hash;    //Default to 0 ### String类中的私有变量，
 3     if (h == 0 && value.length > 0) {    //private final char value[]; ### Sting类中保存的字符串内容的的数组
 4         char val[] = value;
 5 
 6         for (int i = 0; i < value.length; i++) {
 7             h = 31 * h + val[i];
 8         }
 9         hash = h;
10     }
11     return h;
12 }

//没有重写hashCode方法的类，直接返回32位对象在JVM中的地址；Long类重写了hashCode方法，返回计算出的hashCode数值

public class ComHashcode{
 2     public static void main(String[] args) throws Exception {
 3         ComHashcode a = new ComHashcode();
 4         ComHashcode b = new ComHashcode();
 5         System.out.println(a.hashCode());    //870919696
 6         System.out.println(b.hashCode());    //298792720
 7         
 8         Long num1 = new Long(8);
 9         Long num2 = new Long(8);
10         System.out.println(num1.hashCode());    //8
11         System.out.println(num2.hashCode());    //8
12     }
13 }