Thread: Inner Class Use

class Outer
{
   private int temp=9;
   class Inner
   {
      void getData()
      {
          System.out.println("Value of temp is"+temp);
       }
   }
   public static void main(String args[])
   {
      Outer o=new Outer();
      Outer.Inner i=o.new Inner();
      i.getData();
   }
}
[B][/B]

In the code above inner class needs to access outer class variable to perform certain task.
But why can't we just add a instance variable of Outer class in Inner class and keep both classes separate.Why do we need to nest it.What is the need of Inner Classes in java?

Or you could do as you've suggested, and I don't think there's anything wrong with it other than it may be more complicated than it needs to be:

class Outer
{
    private int temp=9;
    class Inner
    {
        int temp;
 
        public Inner( int temp )
        {
            this.temp = temp;
        }
 
        void getData()
        {
            System.out.println("Value of inner class temp is " + temp );
        }
    }
    public static void main(String args[])
    {
        Outer o=new Outer();
        Outer.Inner i=o.new Inner( o.temp );
        i.getData();
    }
}

Hello,
Your code is also using inner class.I wan't to know why can't we separate the two classes as independent and with the help of getter methods of Outer Inner class , Inner class can access it's variable.Why do we need to nest it?

regards
Swapneel

Who says you can't? Of course you can do exactly as you described. Unless you're in a class and the teacher tells you one way will get a good grade and another way will get a bad grade. Do the way that will get the good grade.