Why does this give error?

Question

Why does this give error and Cat is not an abstract class?
it's a code written in java tutorial and the method was void. I just changed it to String to have return a value.but it doesn't work.why? What's the problem? the method must be only void type?

abstract class Animal {
int legs = 0;
abstract String makeSound();
}

class Cat extends Animal {
public String makeSound(String a) {
String b = a + " world";
return b;
}
}

public class Program {
public static void main(String[] args) {
Cat c = new Cat();
System.out.println(c.makeSound("Hello"));
}
}
https://code.sololearn.com/c7p8JWPLEXDO/?ref=app

Answer 1

In abstract class method makeSound don't take any parameter but class Cat has parameter.
In general, you didn't override method from abstract class in cat class.

Answer 2

salar vhd no problem, good luck 😄

Answer 3

Yeaaaah That's right. I thought we can't include any parameter in abstract method in abstract class. Thank you :))