Java重载和重写函数调用

class A {
    void meth(A a) { System.out.println("A a.meth() called"); }
    void meth(D d) { System.out.println("A d.meth() called"); }
    void meth(E e) { System.out.println("A e.meth() called"); }
}

class D {}

class E extends D {}

class B extends A {
    void meth(A a) { System.out.println("B a.meth() called"); }
    void meth(B b) { System.out.println("B b.meth() called"); }
    void meth(D d) { System.out.println("B d.meth() called"); }
    void meth(E e) { System.out.println("B e.meth() called"); }
}


public class OverldOverd {
    public static void main (String[] args) {
        B b = new B();
        A a = b;

        a.meth(a);    // B a.meth() called
        a.meth(b);    // B a.meth() called /*! Why? !*/
    }
}

a.meth(b);

B b.meth() called

显然我错了。我在想办法。有人能帮我理解我错在哪里吗?如果我的算法错误,请告诉我。提前谢谢。