自动调用toString方法—— 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 //A.java public class A extends B { public String toString() { return "A"; } } //B.java public class B { public String toString() { [...]
