I give my tongue to...the cat (french expression)

3.) The creation of the objects: Chat chat1 = new Chat(); and the assigning values to the fields of the objects: chat1.age = 5; all these should be written in the main() method, not in the combratte() instance method.

package fr.codegym.task.task05.task0502;

/*
Implémenter la méthode combattre
*/

public class Chat {
    public int age;
    public int poids;
    public int force;

    public Chat() {
    }

    public boolean combattre(Chat autreChat) {
        //écris ton code ici

        Chat chat1 = new Chat();
        Chat chat2 = new Chat();
        chat1.age = 5;
        chat1.poids = 6;
        chat1.force = 10;

        chat2.age = 3;
        chat2.poids = 4;
        chat2.force = 5;

        if (this.force > autreChat.force) {
            return true;
        }
        else if (this.force > autreChat.force) {
            return false;
        }
            return false;
    }

    public static void main(String[] args) {

    }
}

1.) The public boolean combattre(Chat autreChat) method is a "generic" code. Every Chat object you create will have its own combratte() method like this! You understand: if you create chat1 chat2 chat3 . . . chat48 objects, each of our 48 objects will have its own combratte() method! That's why we call such a method an instance method. Every instance (=object) will have one instance of this method. So you can't write 'chat1' variable name in this method, because it's not even sure if an object with such a name will ever be created. Maybe an object called chatDelta or chat1984 will be created... Therefore, you can only write code in the instance method with a general formulation. You can refer to 'this' in an instance method. This means the object whose method we are talking about. The one that called the method: If you write this code in main(): chat1.combratte(chat39); // = we call the combratte method of the chat1 object; then 'this' keyword inside the method will mean chat1 object, and the chat39 sent as an argument will be named variable autreChat inside the method. If you write this code in main(): chat19.combratte(chat39); then 'this' keyword inside the method will mean chat19 object. So, inside the boolean instance method, it's incorrect to write this: chat1.force<chat39.force; but you can write for example this code: this.force<autreChat.force; 2.) line 29: if (chat1.force > chat2.force) // in the given case, in your code: 10 > 5 = true line 31: if (chat2.force < chat1.force) // in the given case, in your code: 5 < 10 = true so, you make the exactly same checking in these two lines. Just with other words:) Instead, you could use the if-else structure, for example this way: if (condition) return true; else return false; and you don't need the third return statement (line 34). If you still have questions: Reply button!:)

See my comment on the English version of the task