Find closest value in BST

closestValue.java

import java.util.*;

class Program {
  public static int findClosestValueInBst(BST tree, int target) {
    return findClosestValueInBst(tree, target, tree.value);
	}
	
	public static int findClosestValueInBst(BST tree, int target, int closest){
		// find current and next value
		int currentValue = Math.abs(target - closest);
		int potentialValue = Math.abs(target - tree.value);
		
		// set this if closer node is found while searching tree
		if(currentValue > potentialValue){
			closest = tree.value;
		}
		
		// move left or right in tree if safe
		if(target < tree.value && tree.left != null){
			return findClosestValueInBst(tree.left, target, closest);
		}else if(target > tree.value && tree.right != null){
			return findClosestValueInBst(tree.right, target, closest);
		}else{
			// base case, tree cant be navigated further
			return closest;
		}
	}


  static class BST {
    public int value;
    public BST left;
    public BST right;

    public BST(int value) {
      this.value = value;
    }
  }
}