import java.util.*; public class MyLinkedListQueue {   class Node   {      public Object data;      public Node next;      private Node first;      public MyLinkedListQueue()   {       first = null;   }   public Object peek()   {     if(first==null)     {       throw new NoSuchElementException();     }       return first.data;   }   public void enqueue(Object element)   {      Node newNode = new newNode();      newNode.data = element;      newNode.next = first;      first = newNode;   }   public boolean isEmpty()   {     return(first==null);   }   public int size()   {      int count = 0;      Node p = first;      while(p ==! null)      {        count++;        p = p.next;      }      return count;   }     }  } Hello, I am getting an error message when I execute this program. This is what I get: MyLinkedListQueue.java:11: error: invalid method declaration; return type required   public MyLinkedListQueue()          ^ 1 error I also need to have a dequeue method in my program. It is very similar to the enqueue method.  I'll appreciate the help, Thanks!

import java.util.*;
public class MyLinkedListQueue
{

  class Node
  {
     public Object data;
     public Node next;
     private Node first;
  
  public MyLinkedListQueue()
  {
      first = null;
  }
  public Object peek()
  {
    if(first==null)
    {
      throw new NoSuchElementException();
    }
      return first.data;
  }
  public void enqueue(Object element)
  {
     Node newNode = new newNode();
     newNode.data = element;
     newNode.next = first;
     first = newNode;
  }
  public boolean isEmpty()
  {
    return(first==null);
  }
  public int size()
  {
     int count = 0;
     Node p = first;
     while(p ==! null)
     {
       count++;
       p = p.next;
     }
     return count;
  }
  
 }
 }

Hello, I am getting an error message when I execute this program. This is what I get:

MyLinkedListQueue.java:11: error: invalid method declaration; return type required
  public MyLinkedListQueue()
         ^
1 error

I also need to have a dequeue method in my program. It is very similar to the enqueue method. 

I'll appreciate the help, Thanks!