java anonymous class as parameter with new methods

Question

When I search for the method by reflection it shows the newly provided method. But I don't know how to invoke that method, if someone has got any idea how to do it please tell me.

//some pakage
pakage xyz;

class A {
    // a simple method of class A
    public void aMethod() {
        //simple print statement
        System.out.println("A class method");
    }
}

class B {
    // a method of class B that takes A types as an argument
    public void bMethod(A arg) {
        Class c = Class.forName("xyz.A");

        Method[] methods = c.getDeclaredMethods();
        for (Method method : methods) {
            System.out.println(method.getName());
        }
    }
}

class Test {
    public static void main(String[] args) {
        B bObj = new B();
        bObj.bMethod(new A() {
            public void anotherMethod() {
                System.out.println("another method");
            }
        });
    }
}

I formatted your question and your code, and fixed the obvious mistakes. Next time, I'll just downvote. Take some care when writing a question. — JB Nizet, May 31 '17 at 08:36
You should also explain what you're trying to achieve, at a much higher level. Why are you using reflection? Why are you using such anonymous classes with additional methods that no one can call. But anyway, if you want to find this additional method, you need to get the methods of the class of `arg`. Not the methods of A. — JB Nizet, May 31 '17 at 08:38

Krzysztof Cichocki · Answer 1 · 2017-06-01T10:30:04.700

0

You can use reflection to invoke the method on particular object:

public void invokeSomeMethodOnA(A arg, String methodName) {
    Method method = arg.getClass().getDeclaredMethod(methodName);

    //To invoke the method:
    method.invoke(arg, parameters here);
}

edited Jun 01 '17 at 10:30

answered May 31 '17 at 08:42

Krzysztof Cichocki

6,294
1
16
32

method.invoke(obj, parameters here);is it is the same object(obj) in parameter? – Ankur Jun 01 '17 at 10:21
Yes, the method will be invoked on the same object as in parameter. – Krzysztof Cichocki Jun 01 '17 at 10:28
Ok Thank You krzysztof-cichocki – Ankur Jun 01 '17 at 10:29

score 0 · Answer 2 · answered May 31 '17 at 08:48

I suppose maybe this is what you want.

package xyz;

import java.lang.reflect.Method;

class A {
    // a simple method of class A
    public void aMethod() {
        //simple print statement
        System.out.println("A class method");
    }
}

class B {
    // a method of class B that takes A types as an argument
    public void bMethod(A arg) throws Exception {
        Class c = Class.forName(arg.getClass().getName());

        Method[] methods = c.getDeclaredMethods();
        for (Method method : methods) {
            System.out.println(method.getName());
            method.invoke(arg);
        }
    }
}

class Test {
    public static void main(String[] args) throws Exception {
        B bObj = new B();
        bObj.bMethod(new A() {
            public void anotherMethod() {
                System.out.println("another method");
            }
        });
    }
}

java anonymous class as parameter with new methods

2 Answers2