java Program to know an element in Binary tree

public class BinaryTree {
Node root;
class Node {
    int value;
    Node left;
    Node right;
 
     Node(int value) {
        this.value = value;
        right = null;
        left = null;
    }
}
private Node addRecursive(Node current, int value) {
    if (current == null) {
        return new Node(value);
    }
 
    if (value < current.value) {
        current.left = addRecursive(current.left, value);
    } else if (value > current.value) {
        current.right = addRecursive(current.right, value);
    } else {
        // value already exists
        return current;
    }
 
    return current;
}
public void add(int value) {
    root = addRecursive(root, value);
}
private BinaryTree createBinaryTree() {
    BinaryTree bt = new BinaryTree();
 
    bt.add(6);
    bt.add(4);
    bt.add(8);
    bt.add(3);
    bt.add(5);
    bt.add(7);
    bt.add(9);
 
    return bt;
}
private boolean containsNodeRecursive(Node current, int value) {
    if (current == null) {
        return false;
    } 
    if (value == current.value) {
        return true;
    } 
    return value < current.value
      ? containsNodeRecursive(current.left, value)
      : containsNodeRecursive(current.right, value);
}
public boolean containsNode(int value) {
    return containsNodeRecursive(root, value);
}
public void givenABinaryTree_WhenAddingElements_ThenTreeContainsThoseElements() {
    BinaryTree bt = createBinaryTree();

    assertTrue(bt.containsNode(6));
    assertTrue(bt.containsNode(4));
 
    assertFalse(bt.containsNode(1));
}
public static void main(String[] args){
 BinaryTree bt=new BinaryTree();
bt.givenABinaryTree_WhenAddingElements_ThenTreeContainsThoseElements();
}
}