Starter code for remove

MyBinarySearchTree.java

public class MyBinarySearchTree {

  private MyTreeNode root;

  public MyBinarySearchTree() {
    this.root = null;
  }

  public void add(Integer data) throws Exception {
    this.root = add(root, data);
  }

  private MyTreeNode add(MyTreeNode node, Integer data) throws Exception {
    if (node == null) {
      return new MyTreeNode(data);
    } else if (node.getData().equals(data)) {
      throw new Exception("Item is already in the tree");
    }

    if (data < node.getData()) {
      node.setLeft(add(node.getLeft(), data));
    } else if (data > node.getData()) {
      node.setRight(add(node.getRight(), data));
    }
    return node;
  }

  public void remove(Integer data) {
    root = remove(root, data);
  }

  public MyTreeNode remove(MyTreeNode node, Integer data) {

  }

  private MyTreeNode succ(MyTreeNode node) {
    if (node == null) {
      return null;
    }
    return min(node.getRight());
  }

  private MyTreeNode min(MyTreeNode node) {
    if (node == null) {
      return null;
    } else if (node.getLeft() == null) {
      return node;
    } else {
      return min(node.getLeft());
    }
  }


  public boolean contains(Integer data) {
    return contains(root, data);
  }

  private boolean contains(MyTreeNode root, Integer data) {
    if (root == null) {
      return false;
    } else if (root.getData() < data) {
      return contains(root.getLeft(), data);
    } else if(root.getData() > data)  {
      return contains(root.getRight(), data);
    } else {
      return true;
    }
  }

  public String toString() {
    return toString(root);
  }

  private String toString(MyTreeNode root) {
    if (root == null) {
      return "";
    } else {
      return toString(root.getLeft()) + root.getData() + " " + toString(root.getRight());
    }
  }


  private class MyTreeNode {
    private Integer data;
    private MyTreeNode left;
    private MyTreeNode right;

    public MyTreeNode(Integer data) {
      this.data = data;
      this.left = null;
      this.right = null;
    }

    public MyTreeNode(Integer data, MyTreeNode left, MyTreeNode right) {
      this.data = data;
      this.left = left;
      this.right = right;
    }

    public Integer getData() {
      return data;
    }

    public void setData(Integer data) {
      this.data = data;
    }

    public MyTreeNode getLeft() {
      return left;
    }

    public void setLeft(MyTreeNode left) {
      this.left = left;
    }

    public MyTreeNode getRight() {
      return right;
    }

    public void setRight(MyTreeNode right) {
      this.right = right;
    }

  }
}

MyBinarySearchTreeTest.java

import junit.framework.TestCase;
import org.junit.Test;


public class MyBinarySearchTreeTest extends TestCase {
   MyBinarySearchTree tree;

   @Override
   protected void setUp() throws Exception {
      tree = new MyBinarySearchTree();
   }

   @Test
   public void testAdd() throws Exception {
      tree.add(15);
      assertTrue(tree.contains(15));
   }

   @Test
   public void testAddMany() throws Exception {
      tree.add(5);
      tree.add(10);
      tree.add(30);
      tree.add(20);
      tree.add(40);
      assertEquals(tree.toString(), "5 10 20 30 40 ");
   }

   @Test
   public void testRemove() throws Exception {
      tree.add(15);
      tree.add(20);
      tree.remove(15);
      assertFalse(tree.contains(15));
      assertTrue(tree.contains(20));
   }

   @Test
   public void testContains() throws Exception {
      tree.add(5);
      tree.add(10);
      tree.add(30);
      tree.add(20);
      tree.add(40);
      assertTrue(tree.contains(5));
      assertFalse(tree.contains(16));
   }


}