How do I extend and implement same method from an abstract class and interface

I have a method with same signature (arguments & return type) in an abstract class and interface. I want to extend the abstract class and implement the interface in a single class. how can I do that.... please help

Code:

interface Acceptable {
public void accept ();
}

public abstract class AbstractAccept {
public abstract void accept (); // updated the code, forgot to add abstract first time
}

public class ConcreteAccept extends AbstractAccept implements Acceptable {
//// implementation code goes here
}

What have you tried so far? What's your first guess?

Tried to implement both the methods as a same method. as below but it is throwing a NoClassDefFoundError

Code: //
public class test extends AbstractAccept implements Acceptable {
public void accept(){
System.out.println("running Successfully");
}
public static void main (String[] args) {
(new test()).accept();
}
}

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