[java] Binary Search Tree - Java Implementation

This program has a functions for

1. Add Node
2. Display BST(Inorder)
3. Find Element

4. Find Successor

   class BNode{
       int data;
       BNode left, right;
   
       public BNode(int data){
           this.data = data;
           this.left = null;
           this.right = null;
       }
   }
   
   public class BST {
       static BNode root;
   
       public int add(int value){
           BNode newNode, current;
   
           newNode = new BNode(value);
           if(root == null){
               root = newNode;
               current = root;
           }
           else{
               current = root;
               while(current.left != null || current.right != null){
                   if(newNode.data < current.data){
                       if(current.left != null)
                           current = current.left;
                       else
                           break;
                   }                   
                   else{
                       if(current.right != null)
                           current = current.right;
                       else
                           break;
                   }                                           
               }
               if(newNode.data < current.data)
                   current.left = newNode;
               else
                   current.right = newNode;
           }
   
           return value;
       }
   
       public void inorder(BNode root){
           if (root != null) {
               inorder(root.left);
               System.out.println(root.data);
               inorder(root.right);
           }
       }
   
       public boolean find(int value){
           boolean flag = false;
           BNode current;
           current = root;
           while(current!= null){
               if(current.data == value){
                   flag = true;
                   break;
               }   
               else if(current.data > value)
                   current = current.left;
               else
                   current = current.right;
           }
           System.out.println("Is "+value+" present in tree? : "+flag);
           return flag;
       }
   
       public void successor(int value){
           BNode current;
           current = root;
   
           if(find(value)){
               while(current.data != value){
                   if(value < current.data && current.left != null){
                       System.out.println("Node is: "+current.data);
                       current = current.left;
                   }
                   else if(value > current.data && current.right != null){
                       System.out.println("Node is: "+current.data);
                       current = current.right;
                   }                   
               }
           }
           else
               System.out.println(value+" Element is not present in tree");
       }
   
       public static void main(String[] args) {
   
           BST b = new BST();
           b.add(50);
           b.add(30);
           b.add(20);
           b.add(40);
           b.add(70);
           b.add(60);
           b.add(80);
           b.add(90);
   
           b.inorder(root);
           b.find(30);
           b.find(90);
           b.find(100);
           b.find(50);
   
           b.successor(90);
           System.out.println();
           b.successor(70);
       }
   
   }