Check out example codes for "how to create an abstract class in java". It will help you in understanding the concepts better.

Code Example 1

public abstract class GraphicObject {

   abstract void draw();

Code Example 2

abstract class scratch{

Code Example 3

abstract class Scratch{
  // cannot be static
    abstract public void hello();
    abstract String randNum();

interface Other{
  //all methods in an interface are abstract
    public void bye();
    String randDouble();

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