Simple Program

class A
{
   private int x=10;
   protected int y=20;
   public int z;
 
   void myA()
   {
      //All variables accessed inside class
      System.out.println(x+" "+y+" "+z);
   }
}

class B extends A
{
   void myB()
   {
      //public & protected variable accessed in  Subclass.
      System.out.println(y+" "+z);
   }
}

class C
{
   public static void main ( String s[])
   {
  
  A a=new A();    
  B b=new B();
   a.z=30;    // public variable accessed anywhere in program
   b.z=30;
   a.myA();
   b.myB();
  
   }
}

Output