方法的选择

标签：upd   occurs   err   val   html   14.   extends   example   instance   

解读JLS：https://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.12.3

If the compile-time declaration is void, then the method invocation must be a top level expression (that is, the Expression in an expression statement (§14.8) or in the ForInit or ForUpdate part of a for statement (§14.14)), or a compile-time error occurs.

class T1 {
	public void a(){}
	public void b(){}
	public void test(int i){
		for(a();i<0;i++,b()){
			
		}
	}
}

解读JLS：https://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.12.4.2

When accessing an instance variable, super means the same as a cast of this (§15.11.2), but this equivalence does not hold true for method invocation. This is demonstrated by the example:

class T1 {
	int a = 1;
}

class T2 extends T1 {
	int a = 2;
}

class T3 extends T2 {
	public void test() {
		System.out.println(((T1) this).a);
		System.out.println(((T2) this).a);
	}
}

public class TestB {
	public static void main(String[] args) {
		T3 t3 = new T3();
		t3.test();
	}
}

打印的结果为1、2　　

方法的选择

标签：upd   occurs   err   val   html   14.   extends   example   instance   

原文地址：https://www.cnblogs.com/extjs4/p/9249414.html