Java Integer对象的比较方式

ArrayList<Integer> list = new ArrayList(); 
list.add(3);
list.add(Integer.valueOf(3));

    public static Integer valueOf(int i) {
        if (i >= IntegerCache.low && i <= IntegerCache.high)
            return IntegerCache.cache[i + (-IntegerCache.low)];
        return new Integer(i);
    }

 private static class IntegerCache {
        static final int low = -128;
        static final int high;
        static final Integer cache[]; 
        static {
            // high value may be configured by property
            int h = 127;
            String integerCacheHighPropValue =
                VM.getSavedProperty("java.lang.Integer.IntegerCache.high");
            if (integerCacheHighPropValue != null) {
                try {
                    int i = parseInt(integerCacheHighPropValue);
                    i = Math.max(i, 127);
                    // Maximum array size is Integer.MAX_VALUE
                    h = Math.min(i, Integer.MAX_VALUE - (-low) -1);
                } catch( NumberFormatException nfe) {
                    // If the property cannot be parsed into an int, ignore it.
                }
            }
            high = h;
 
            cache = new Integer[(high - low) + 1];
            int j = low;
            for(int k = 0; k < cache.length; k++)
                cache[k] = new Integer(j++);
 
            // range [-128, 127] must be interned (JLS7 5.1.7)
            assert IntegerCache.high >= 127;
        }
 
        private IntegerCache() {}
    }

int n = list.get(i);
int n = list.get(i).intValue();

    public int intValue() {
        return value;
    }

Integer n1 = 3;
Integer n1 = Integer.valueOf(3);

Integer n2 = new Integer(3);

        Integer n1 = new Integer(47);
        Integer n2 = new Integer(47);
        Integer n3 = 47;
        Integer n4 = 47;
        Integer n5 = 200;
        Integer n6 = 200;
 
        System.out.println(n1 == n2);   //false，两个new的对象
        System.out.println(n1 == n3);   //false  n1在堆中，n3指向IntegerCache缓存（方法区中）
        System.out.println(n3 == n4);   //true   都指向缓存中同一个对象
        System.out.println(n5 == n6);   //false  超出缓存范围，分别是两个new出来的对象

    public boolean equals(Object obj) {
        if (obj instanceof Integer) {
            return value == ((Integer)obj).intValue();
        }
        return false;
    }

Integer l1 = 122;
Integer l2 = 122;
if(l1 == l2)
    System.out.println("Right");
else
    System.out.println("Wrong");

Integer l1 = 233;
Integer l2 = 233;
if(l1 == l2)
    System.out.println("Right");
else
    System.out.println("Wrong");

Integer l1 = 233;
int l2 = 233;
if(l1 == l2)
    System.out.println("Right");
else
    System.out.println("Wrong");

Integer l1 = 233;
Integer l2 = new Integer(233);
if(l1 == l2)
    System.out.println("Right");
else
    System.out.println("Wrong");

public static Integer valueOf(int i) {
         assert IntegerCache.high >= 127;
         if (i >= IntegerCache.low && i <= IntegerCache.high)
             return IntegerCache.cache[i + (-IntegerCache.low)];
         return new Integer(i);
     }