What does this error mean?

I am trying to read the data in a file and print it to a new Jtext area. This line:

    this.JTextArea.append(read);

is where I recieve this error:
cannot find symbol variable JTextArea.
I am stumped!

      public class ReadFile
      {
          BufferedReader in;
        String read;
          String output;
          JTextArea show;
          public ReadFile()
          {
              JTextArea show = new JTextArea();
              try
              {
                  //open a buffered reader to file
                  in = new BufferedReader(new FileReader("ContactData.txt"));
                  
                 while ((read = in.readLine()) != null) {
        this.JTextArea.append(read);
              }
              }
              catch(IOException f)
              {
                  System.out.println("There is a problem." + f);
              }
          }
      }