class BSTNode  {      int key;      BSTNode left, right;        public BSTNode(int item) {            key = item;            left = right = null;      } }     class BST_Tree  {            BSTNode root;        BST_Tree()  {   // Constructor            root = null;      }       boolean search(int key){         return (searchRec(root, key) != null);     }          public BSTNode searchRec(BSTNode root, int key) {          if (root==null || root.key==key)            return root;              if (root.key > key)            return searchRec(root.left, key);              return searchRec (root.right, key);     }              void deleteKey(int key) {            root = deleteRec(root, key);      }      /* A recursive function to insert a new key in BST */      BSTNode deleteRec(BSTNode root, int key) {            /* Base Case: If the tree is empty */            if (root == null) return root;              /* Otherwise, recur down the tree */            if (key < root.key)                 root.left = deleteRec(root.left, key);            else if (key > root.key)                 root.right = deleteRec(root.right, key);              // if key is same as root's key, then This is the target           else {                 // node with only one child or no child                 if (root.left == null)                       return root.right;                 else if (root.right == null)                       return root.left;                   // node with two children: Get the inorder successor                 // (smallest in the right subtree)                 root.key = minValue(root.right);                   // Delete the inorder successor                 root.right = deleteRec(root.right, root.key);            }              return root;      }            int minValue(BSTNode root) {            int minv = root.key;            while (root.left != null) {                 minv = root.left.key;                 root = root.left;            }            return minv;      }              void insert(int key) {            root = insertRec(root, key);      }      /* A recursive function to insert a new key in BST */      BSTNode insertRec(BSTNode root, int key) {            /* If the tree is empty, return a new node */            if (root == null) {                 root = new BSTNode(key);                 return root;            }              /* Otherwise, recur down the tree */            if (key < root.key)                 root.left = insertRec(root.left, key);            else if (key > root.key)                 root.right = insertRec(root.right, key);                         return root;      }              void inorder() {            inorderRec(root);      }      // A utility function to do inorder traversal of BST      void inorderRec(BSTNode root) {            if (root != null) {                 inorderRec(root.left);                 System.out.print(root.key + " ");                 inorderRec(root.right);            }      }        void preorder() {            preorderRec(root);      }            void preorderRec(BSTNode root) {            if (root != null) {                 System.out.print(root.key + " ");                 preorderRec(root.left);                 preorderRec(root.right);            }      }        void postorder()      {            postorderRec(root);      }            void postorderRec(BSTNode root) {            if (root != null) {                 postorderRec(root.left);                 postorderRec(root.right);                 System.out.print(root.key + " ");            }      }    }   public class BST_Recursive  {      public static void main(String[] args)  {              BST_Tree tree = new BST_Tree();              System.out.println("Build a tree  by inserting :\n 50 30 20 40 70 60 80");            tree.insert(50);            tree.insert(30);            tree.insert(20);            tree.insert(40);            tree.insert(70);            tree.insert(60);            tree.insert(80);                System.out.println("\nPre-order traversal of the given tree");            tree.preorder();              System.out.println("\nIn-order traversal of the given tree");            tree.inorder();              System.out.println("\nPost-order traversal of the given tree");            tree.postorder();              System.out.println("\n\nDelete 20");            tree.deleteKey(20);              System.out.println("Inorder traversal of the modified tree");            tree.inorder();              System.out.println("\nDelete 30");            tree.deleteKey(30);              System.out.println("Inorder traversal of the modified tree");            tree.inorder();              System.out.println("\nDelete 50");            tree.deleteKey(50);              System.out.println("Inorder traversal of the modified tree");            tree.inorder();              System.out.println("\nSearch 70");            System.out.println("Found ? :  " + tree.search(70) );      } } Task 1:    Modify BST_Recursive.java  to write a complete program to implement a spare-parts database with itemNo, price and description. Provide options to insert, search, delete, and show all items in order of itemNo