Integer
1:包装类
public static void func(Integer a) {
a = 3;
System.out.println(a);
}
public static void main(String[] args) {
// 1)基本类型和包装类型
int a = 100;
Integer b = 100;
System.out.println(a == b);
// 2)两个包装类型
Integer c = 100;
Integer d = 100;
System.out.println(c == d);
// 3)
c = 200;
d = 200;
System.out.println(c == d);
Integer e = new Integer(100);
Integer f = new Integer(100);
System.out.println(e==f);
Integer g = new Integer(10);//变量
func(g);
System.out.println(g);
}