can we create in the same class

[Tomendra Singh]

hi all'
i just want to know that can an object of any class can be created in the same class, if it is? please provide me how?

[Campbell Ritchie]

Not quite sure about your question, but the answer is probably "yes."

You can have a linked list made up of nodes, each with a reference to the next node on the list. This is sometimes called a self-referential class.

public class LinkedListNode<E>
{
   private E value;
   private LinkedListNode next;
 
   public LinkedListNode<E>(E e)
   {
      value = e;
      next = null;
   }
 
   public void addNext(E e)
   {
      if (next == null)
      {
         next = new LinkedNode<E>(e);
      }
      else
      {
         LinkedNode<E> nextNode = new LinkedNode<E>(e);
         nextNode.next = this.next;
         this.next = nextNode;
      }
   }
. . .
}

[Rob Spoor]

Just make sure you don't do that in the constructor (with the same parameters) or directly from the declaration of an instance field or you will get a StackOverflowError:

public class Test
{
    private Test test1; // ok
 
    private Test test2 = new Test(); // problem!
 
    public Test()
    {
        test1 = new Test(); // problem!
    }
 
    public Test(int i)
    {
        test1 = new Test(); // ok unless Test() calls this constructor
    }
}

If we change the first constructor to the following it will also go wrong:

public Test()
{
    this(1); // problem!
}

This is because in all examples documented as problematic, creating a new Test object results in the creating of a new Test object. Which results in the the creating of a new Test object. Which results in the the creating of a new Test object. This will continue until a StackOverflowError is thrown by the JVM.