Program

public class progs
{
  public boolean isLeaf(TreeNode node)
  {
    return  node!=null && node.getLeft()==null && node.getRight()==null;
  }
  public static int sumTree(TreeNode root)
  {
    if(root == null)
      return 0;
    return (Integer)root.getValue() + sumTree(root.getLeft()) + sumTree(root.getRight());
  }
  public static int countPaths(TreeNode root)
  {
    int sum=0;
    if(root==null)
      return 0;
    if(root.getLeft() != null)
      sum += 1+countPaths(root.getLeft());
    if(root.getRight() != null)
      sum += 1+countPaths(root.getRight());
    return sum;
  }
  public static int depth(TreeNode root)
  {
    if(root == null)
      return 0;
    else
      return 1+Math.max(depth(root.getLeft()), depth(root.getRight()));
  }
  public static void main()
  {
    TreeNode head = new TreeNode(1);
    head.setLeft(new TreeNode(2));
    head.setRight(new TreeNode(3));
    head.getRight().setLeft(new TreeNode(6));
    head.getLeft().setLeft(new TreeNode(4));
    head.getLeft().setRight(new TreeNode(5));
    System.out.println(countPaths(head));
    System.out.println("\n" + sumTree(head));
    System.out.println("\n" + depth(head));
    printTree(head);
    
  }
  public static void printTree(TreeNode root)
  {
    if(root==null)
      return;
    printTree(root.getLeft());
    System.out.print(root.getValue()+" ");
    printTree(root.getRight());
  }
  
}