title: Basic I/o token query
body: <pre><code> BufferedReader br = new BufferedReader(new FileReader("data/Catalog.txt"));
  
      String line="";
      arrayList =new ArrayList();
      while((line = br.readLine())!=null)
          {
        //  System.out.println(line);
          StringTokenizer st = new StringTokenizer(line);
          while(st.hasMoreTokens())
              {
              //System.out.println(st.nextToken());
              arrayList.add(st.nextToken());
              }
          }
      }
  </code></pre>
  
  <p>//what is the use of token when reading the file? and what is an arraylist?</p>