First Element of Array being written to file twice Help

[kingkongjaffa]

So I have a few methods: one for retrieving the and incrementing the ID, one for saving the incremented ID , one for Adding the users input to properties and assigning the object to an element of the array, and one for writing the array to a File.

now my problem lies in that the first time i run the program and write to file it writes the first objects properties to 2 elements of the array

This is my code:

public int GetNextID(){
    Entity IDX = new Entity();
        try{
            I = new Scanner (new File(Kudex.IDDATA));
        } catch (Exception e){
            e.printStackTrace();
          } 
        while (I.hasNext()){
            IDX.ID = I.nextInt();
        } 
        return ++IDX.ID; } //opens and increments the ID number
public void savenewid(){   
        try{
            IDWriter = new Formatter (Kudex.IDDATA);
            IDWriter.format("%d",ID );
            IDWriter.close(); //update unique ID file
        }
         catch(Exception e) {
            e.printStackTrace();
        }
       
        
             
    } // saves next unique ID
    
public void AddingCustomer(){
      
      System.out.println("Please enter your customer details:");
      System.out.println("Please enter your first name:"); 
      Scanner firstname = new Scanner (System.in);
      fname  = firstname.nextLine();
      System.out.println("please enter your second name");
      Scanner secondname = new Scanner (System.in);
      sname = secondname.nextLine();
      ID = GetNextID();   //populate object properties
                    
      for (int i = 0 ; i<custArray.length;  i++){
         if(custArray[i]== null){
            custArray[i]= new Customer();
            custArray[i].ID = ID;
            custArray[i].fname = fname;
            custArray[i].sname = sname;
            break;
         } 
      }
    }//populates the next available element in the array with the user input
    
public void WriteCustomersToFile(){
       /*try {
        ClearFile(Kudex.CUSTDATA);
       }
       catch (IllegalArgumentException e){
         e.printStackTrace();
       }
       */
      for (int i = 0 ; i<custArray.length;  i++){
            try {
               
              FileWriter outFile = new FileWriter(Kudex.CUSTDATA,true);
              PrintWriter out = new PrintWriter(outFile);
              
              if (custArray[i] != null){
                String  s = String.format("%d, %s, %s", custArray[i].ID , custArray[i].fname , custArray[i].sname );
                out.println(s);
              }
              out.close();
            }  
            catch (IOException e){
               e.printStackTrace();
            }

      }
   }//writes the contents of the array to customer record file

And this is the order the methods run in : these are running in another class hence the cust. (object) this is not the error this merely illustrates the order they are running in if that is of any relevance.

 cust.GetNextID();
             cust.AddingCustomer();
             cust.WriteCustomersToFile();
             cust.savenewid();

Any Suggestions are appreciated

note: the program runs fine and generates the unique ID as expected and multiple customers can be added however the first time I try to write to an element I get the first elements contents written in 2 elements.

[Norm]

the first time I try to write to an element I get the first elements contents written in 2 elements.

Try adding some debugging code to see where it is happening. Print out the contents of what is added each time it is added to the array to see where the problem is.
Be sure to print out the index and the data.