Binary Search Tree Program in Java

// Binary Tree

import java.util.*;
/*Representing a Node of a binary tree */
class Node
{
  int value;
  Node left, right;
    Node (int value)
  {
    this.value = value;
    left = null;
    right = null;
  }
}
class BTS
{
  Node root;			//root of a binary search tree

    BTS ()
  {
    root = null;
  }

  public void insert (int item)
  {
    root = insertNode (root, item);	//calling inserNode() method
  }

  public Node insertNode (Node root, int item)
  {
    if (root == null)		//if root is null create a new Node
      {
	root = new Node (item);
	return root;
      }
    if (item < root.value)	//if item is less than the current value then traverse left subtree
      root.left = insertNode (root.left, item);
    else if (item > root.value)	//if item is greater than the cureent value then traverse the right subtree
      root.right = insertNode (root.right, item);
    return root;
  }

  public void delete (int value)
  {
    root = deleteNode (root, value);	//calling deleteNode() method
  }

  public Node deleteNode (Node ptr, int value)
  {
    if (ptr == null)
      return ptr;
    if (value < ptr.value)	//if value is less than current value
      ptr.left = deleteNode (ptr.left, value);
    else if (value > ptr.value)	//if value if greater than current value
      ptr.right = deleteNode (ptr.right, value);
    else
      {
	//if node having max one child
	if (ptr.left == null)
	  return ptr.right;
	else if (ptr.right == null)
	  return ptr.left;
	// if node having two children then get the inorder predecessor of node
	ptr.value = minimumValue (ptr.left);
	//delete the inorder predecessor
	ptr.left = deleteNode (ptr.left, ptr.value);
      }
    return ptr;
  }

  //get minimum element in binary search tree
  public int minimumValue (Node ptr)
  {
    int min;
    for (min = ptr.value; ptr.right != null; ptr = ptr.right)
      min = ptr.right.value;
    return min;
  }



  public Node searchNode (Node root, int value)
  {
    if (root == null)
      return null;
    if (root.value == value)	// return true if value is found in binary tree
      return root;
    else if (value < root.value)
      return searchNode (root.left, value);	//traverse left subtree
    else
      return searchNode (root.right, value);	//traverse right subtree
  }
  public void print (Node ptr)
  {
    if (ptr == null)
      return;
    print (ptr.left);
    System.out.print (ptr.value + " ");
    print (ptr.right);
  }
}

public class Main
{
  public static void main (String[]args)
  {
    //Adding Nodes to the binary tree
    BTS tree = new BTS ();
      tree.insert (15);
      tree.insert (19);
      tree.insert (10);
      tree.insert (13);

      tree.print (tree.root);
      System.out.println ();

      tree.delete (15);
      tree.print (tree.root);
      System.out.println ();

    //calling search function if element is found then it will return true else return false
    Node node = tree.searchNode (tree.root, 13);
    if (node != null)
        System.out.println ("Element " + node.value +
			    " is found in binary  tree");
    else
        System.out.println ("Element is not found in binary tree");
  }
}