A question on a build method in a Binary Tree Program

Question

So I'm working on making 20 Questions in java and I'm supposed to make a construct that calls a build method.
I'll post my code as I have it so far.
The game is supposed to work so that there's an original question and then if the user selects yes, then the answer goes to the left link. The no answer goes to the right link and then it keeps going yes for the left, no for the right.
How do I call the build method recursively to do that?
public class GameTree {
* BinaryTreeNode inner class used to create new nodes in the GameTree.
private class BinaryTreeNode {
private String data;
private BinaryTreeNode left;
private BinaryTreeNode right;
BinaryTreeNode(String theData) {
data = theData;
left = null;
right = null;
BinaryTreeNode(String theData, BinaryTreeNode leftLink, BinaryTreeNode rightLink) {
data = theData;
left = leftLink;
right = rightLink;
* instance variables.
private BinaryTreeNode root;
private Scanner my_inputFile;
private String currentFileName;
private BinaryTreeNode currentNodeReferenceInTree;
* Constructor needed to create the game.
* @param name
* this is the name of the file we need to import the game questions
* and answers from.
public GameTree(String name) {
// TODO: Complete this method
     currentFileName = name;
     try {
          my_inputFile = new Scanner(new File(currentFileName));
     catch (FileNotFoundException e) {
     root = build();
     my_inputFile.close();
public BinaryTreeNode build() {
     String token2 = my_inputFile.nextLine();
     if(!isQuestion(token2))
          return new BinaryTreeNode(token2);
     else{
          BinaryTreeNode rightTreeSide = build();
          BinaryTreeNode leftTreeSide = build();
          return new BinaryTreeNode(token2,leftTreeSide, rightTreeSide);
* Ask the game to update the current node by going left for Choice.yes or
* right for Choice.no Example code: theGame.playerSelected(Choice.Yes);
* @param yesOrNo
public void playerSelected(Choice yesOrNo) {
     if(userSelection == Choice.No)
          currentNodeReferenceInTree = currentNodeReferenceInTree.right;
     if(userSelection == Choice.Yes)
          currentNodeReferenceInTree = currentNodeReferenceInTree.left;
I have a separate .java that already says
public enum Choice {
Yes, No
};

Answer 1

When you post code, wrap it in code tags so it's legible. When you're inputting the text, highlight it, and then click the "CODE" button above the text input box. It can be almost impossible to read code that's not formatted like that.
You ask "How do I call the build method recursively to do that?" You don't call recursive methods any differently than you call any other kind of method. Can you clarify what difficulty you're having?