Please Help - Writing JFileChooser with Exception Handling

[verbalh]

I have been trying to write a program that will loop until a user selects a file with a Try - Catch statements to no success. If user hits Cancel then I need NullPointerException or if no file found I need a FileNotFoundException

Here my Instructions:

****************Instructions**************

Write a GUI program that prompts the user to browse and select a file. Then read the selected file using a Scanner object, a line at a time. Copy the file contents and display it in a text area component. If the user did not select a file, then inform the user (using a pop-up window) that a file must be selected and then prompt the user to select a file. Repeat this until the user selects a file. Provide (copy and paste) your Java Source codes.

• If selected file does not exist, then scanner object may throw a FileNotFoundException.
• If user selects “Cancel” option in the file open dialog, the scanner object may throw a NullPointerException
• Think carefully about how to use the try/catch structure in combination with a loop that prompts the user to browse and select a file.

****************Instructions****************

I have this much so far

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//********************************************************************
// DisplayFile.java Author:
//
//
//********************************************************************

import java.util.Scanner;
import java.io.*;
import javax.swing.*;

public class DisplayFile
{
//-----------------------------------------------------------------
// Opens a file chooser dialog, reads the selected file and
// loads it into a text area.
//-----------------------------------------------------------------
public static void main (String[] args) throws IOException
{
JFrame frame = new JFrame ("Display File");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);

JTextArea ta = new JTextArea (20, 30);
JFileChooser chooser = new JFileChooser();

int status = chooser.showOpenDialog (null);

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Please help