Construct a Binary search tree

If you are given a number N, build a binary search tree of size N with node values from 1 to N.

public class BuildTree {

 public Node getTree(int n) {
  if (n <= 0) {
   System.out
     .println("Asking for constructing a tree of size zero or negative number.");
   return null;
  }
  return buildTree(1, n);
 }

 public Node buildTree(int left, int right) {
  if (left > right)
   return null;

  int rootValue = (int) Math.floor((left + right) / 2);
  Node node = new Node(rootValue);
  node.left = buildTree(left, rootValue - 1);
  node.right = buildTree(rootValue + 1, right);
  return node;
 }

 public static class Node {

  public int value;
  // member variables will be initialized to null by default.
  public Node left;
  public Node right;

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

  public Node(int value, Node left, Node right) {
   this.value = value;
   this.left = left;
   this.right = right;
  }
 }
}