Tree Traversal in JAVA (InOder/preOrder/postOrder)

public void inorder(Node root)
 {
  
  if(root==null)
  {
  return;
  }
  
  inorder(root.left);
  System.out.print(root.data+",");
  inorder(root.right);
  
  }
 
 public void preOrder(Node root)
 {
  
  if(root==null)
  {
  return;
  }
  
  System.out.print(root.data+",");
  preOrder(root.left);
  preOrder(root.right);
  
  }
 public void postOrder(Node root)
 {
  
  if(root==null)
  {
  return;
  }
  
  postOrder(root.left);
  
  postOrder(root.right);
  System.out.print(root.data+",");
  }