Binary Search Tree in Java implementation (reference based, dynamic memory)

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import java.util.Scanner; class BST { static BST.Node root = null; public void insert(int num) { if (root == null) { root = new BST.Node(num); } else {// root node is not empty BST.Node temp = root; while (temp != null) { if (num <= temp.getVal()) { if (temp.getLeft() != null) temp = temp.getLeft(); else { temp.setLeft(new Node(num)); break; } } else { if (temp.getRight() != null) temp = temp.getRight(); else { temp.setRight(new Node(num)); break; } } } } } public void search(int num, Node root) { if (root == null) { System.out.println("Number is not present "); return; } if (root.getVal() == num) { System.out.println("Number is present "); } else { if (num < root.getVal()) search(num, root.getLeft()); else search(num, root.getRight()); } } public void display(Node root) { if (root == null) return; display(root.getLeft()); System.out.println(" " + root.getVal() + " "); display(root.getRight()); } public static void main(String[] args) { BST bst= new BST(); byte choice = 0; while (choice != 4) { int num; Scanner in = new Scanner(System.in); System.out.print("\nPress \n1 to insert \n2. To search \n3. Display \n4 to exit->"); choice = in.nextByte(); switch (choice) { case 1: System.out.print("Enter the number ->"); num = in.nextInt(); bst.insert(num); break; case 2: System.out.print("Enter the Number "); num = in.nextInt(); bst.search(num, root); break; case 3: bst.display(root); } } } private static class Node { private int val; private Node left = null; private Node right = null; public Node(int i) { this.val = i; } public int getVal() { return val; } public void setVal(int val) { this.val = val; } public Node getLeft() { return left; } public void setLeft(Node left) { this.left = left; } public Node getRight() { return right; } public void setRight(Node right) { this.right = right; } } }