I want to redirect the Standard System input to JTextField, So that a user must type his/her input in JTextField (instead of console.)

I found System.setIn(InputStream istream) for redirecting System.in.

Here is my scratch code where i confused on reading from JTextField - inputJTextField.

 System.setIn(new InputStream() {
     @Override
         public int read() throws IOException {
         //how to read content?
         return Integer.parseInt(inputJTextField.getText());
      }
  });

My Question is how to read content from GUI Component ( like JTextField and Cast it to String and other types after redirecting the input stream?