方法覆盖

[yjava]

class Homer {
char doh(char c) {
System.out.println("doh(char)");
return 'd';
}
float doh(float f) {
System.out.println("doh(float)");
return 1.0f;
}
}

class Milhouse {}

class Bart extends Homer {
void doh(Milhouse m) {}

}
}

class Hide {
public static void main(String[] args) {
Bart b = new Bart();
b.doh(1); // doh(float) used
b.doh('x');
b.doh(1.0f);
b.doh(new Milhouse());
}
如果把float doh(float f)写在Bart中，既
class Homer {
char doh(char c) {
System.out.println("doh(char)");
return 'd';
}
float doh(float f) {
System.out.println("doh(float)");
return 1.0f;
}
}

class Milhouse {}

class Bart extends Homer {
void doh(Milhouse m) {}
float doh(float f) {
System.out.println("doh(float)");
return 1.0f;
}
}

class Hide {
public static void main(String[] args) {
Bart b = new Bart();
b.doh(1); // doh(float) used
b.doh('x');
b.doh(1.0f);
b.doh(new Milhouse());
}
再编译时b.doh('x');就有问题了，
Hide.java:31: reference to doh is ambiguous, both method doh(char) in Homer and
method doh(float) in Bart match
b.doh('x');
^
不明白为什么会这样，我认为，Bart extends Homer，完全复写一个方法有什么不对，不复写能运行！