Java For Android Tutorial #20: Abstraction Basics

Code:

package com.example;
public class java {

    public static void main(String[] str) {

        Parent parent = new Parent();

    }

}

abstract class Parent{

    public void method1(){}

    public abstract void method2();

}

class Child extends Parent{

    @Override

    public void method2(){}

}

Abstractions provide coders with simple options. Abstraction is about going after ideas rather than
Rule#1: Abstract methods can't be declared in the non-abstract class.
 going into the implementation details. And there are certain rules you have to take care of:
Rule#2: You can't create an object of an abstract class. You have to use it by creating a subclass.
Rule#3: If you are creating a subclass of an abstract class, it is necessary to implement all the abstract methods of the parent abstract class.
Rule#4: An abstract class can have non-abstract methods.