how panache handles abstract class in java

1interface methods{
2    public void hey();
3    public void bye();
4}
5
6//unable to implement all the abstract methods in the interface so 
7// the other class automatically becomes abstract
8abstract class other implements methods{
9    public void hey(){
10        System.out.println("Hey");
11    }
12}
13
14//able to implement all the methods so is not abstract
15class scratch implements methods {
16    public void hey(){
17        System.out.println("Hey");
18    }
19    public void bye() {
20        System.out.println("Hey");
21    }
22}

1abstract class scratch{
2  
3}

1//interface declaration
2interface Polygon_Shape {
3    void calculateArea(int length, int breadth);
4}
5 
6//implement the interface
7class Rectangle implements Polygon_Shape {
8    //implement the interface method
9    public void calculateArea(int length, int breadth) {
10        System.out.println("The area of the rectangle is " + (length * breadth));
11    }
12}
13 
14class Main {
15    public static void main(String[] args) {
16        Rectangle rect = new Rectangle();       //declare a class object
17        rect.calculateArea(10, 20);             //call the method
18    }
19}
20