Binary Search Tree In-Order Traversal

Consider the TreeTest class shown below. What is printed when its main method is executed?

public class TreeTest {
    static class Node {
        int data;
        Node left, right;
        Node(int value) { data = value; }
    }
    public static Node insert(Node root, int value) {
        if(root == null) {
            return new Node(value);
        }
        if(value < root.data) {
            root.left = insert(root.left, value);
        } else if(value > root.data) {
            root.right = insert(root.right, value);
        }
        return root;
    }
    public static void inOrder(Node root) {
        if(root == null) return;
        inOrder(root.left);
        System.out.print(root.data + " ");
        inOrder(root.right);
    }
    public static void main(String[] args) {
        Node root = null;
        int[] vals = {10, 5, 15, 12, 18};
        for(int v : vals) {
            root = insert(root, v);
        }
        inOrder(root);
    }
}