由一个bug引出java包装类型

 1         int a = 5;
 2         Integer b = 5;
 3         Integer c = Integer.valueOf(5);
 4         Integer d = Integer.valueOf(5);
 5         Integer e = new Integer(5);
 6         
 7         System.out.println("测试1，a == b 的结果：" + (a == b));
 8         System.out.println("测试2，b == c 的结果：" + (b == c));
 9         System.out.println("测试3，c == d 的结果：" + (c == d));
10         System.out.println("测试4，d == e 的结果：" + (d == e));
11         System.out.println("测试5，b == e 的结果：" + (b == e));