Generic return type problem that i have mention via comment in my code

// method to get middle element of LinkedList of generic Type;
public T getMiddle()
{

    Node fast = root ;
        Node slow = root ;

    if (root == null){
       System.out.println("List is Empty ");

        //Question -----------
        //if we have generic method and root is null then we have to return a value
        // what should i return here ?? 
     
      // return slow.data;// 

    }else{
        
       
        
        while(fast.next !=null && fast.next.next != null ){
            
            fast = fast.next.next; 
            slow = slow.next; 
            
        }
        
        return slow.data;
        
    }
  }

Return null ____________&