How to return an arraylist from a method

Question

Hello.

---

I need help. For this specific method. I am trying to get it to return an arraylist that I tokenized.

public ArrayList read (){

  BufferedReader inputStream = null;
  try {
    inputStream = new BufferedReader(new FileReader("processes1.txt"));
    String l;
    while ((l = inputStream.readLine()) != null) {

      ArrayList<String> tokens = new ArrayList<String>();

      Scanner tokenize = new Scanner(l);
      while (tokenize.hasNext()) {
        tokens.add(tokenize.next());
      }
      return tokens;
    }
  } catch(IOException ioe){
    ArrayList<String> nothing = new ArrayList<String>();
    nothing.add("error1");
    System.out.println("error");
    //return nothing;
  }
  return tokens;
}

What am I doing wrong?!

Answer 1

At the very end you are doing return tokens but that variable was defined INSIDE the try block, so it is not accessible outside of it. You should add:

ArrayList<String> tokens = new ArrayList<String>();

to the top of your method, just under the BufferedReader.

Answer 2

Try returning ArrayList which is the more appropriate return type in this case. Generic types aren't related to each other the way your example seems to be using them.

Answer 3

It is probably an error in your main method somewhere. Are you instantiating the class and calling the method read() on it?