errors in Hashtable to HashMap

From:

bH <bherbst65@hotmail.com>

Newsgroups:

comp.lang.java.help

Date:

Fri, 2 May 2008 05:34:40 -0700 (PDT)

Message-ID:

<589c4c74-81c5-4e28-a36e-a18cf975064d@l42g2000hsc.googlegroups.com>

Hi All,

This is a scaled down version of the program:
http://sio.midco.net/dfranklin/phonedial/index.html

I am trying to revise the program that was constructed originally
with a Hashtable to HashMap.
This revision below compiles with no error.
The HashMap item will correctly identify at the line:
    System.out.println("Test line 1");
    String btn3 = buttonSoundNames.get(keyPad.b3);
    // will show "3.au"

But in the second instance it will not correctly identify the button
being pressed at the line:
       System.out.println("Test line 2");
      String name = new String((String)
buttonSoundNames.get((Button)e.target));
      System.out.println(name);
      //fails to identify the key press name
      //"1.au" or "2.au" or "3.au" is expected

The runtime error list is:
Exception in thread "AWT-EventQueue-2" java.lang.NullPointerException
    at TestPhneDialer.action(TestPhneDialer.java:30)
    at java.awt.Component.handleEvent(Unknown Source)
    at java.awt.Component.postEvent(Unknown Source)
    at java.awt.Component.postEvent(Unknown Source)
    at java.awt.Component.postEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown
Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown
Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

import java.applet.*;
import java.awt.*;
import java.util.HashMap;

public class TestPhneDialer extends Applet {
  boolean DEBUG = false;
  HashMap buttonSoundNames;
  KeyPad keyPad;

  public void init() {
    keyPad = new KeyPad();
    HashMap<Button,String>buttonSoundNames =
new HashMap<Button,String>(3,3);

    buttonSoundNames.put(keyPad.b1, "1.au");
    buttonSoundNames.put(keyPad.b2, "2.au");
    buttonSoundNames.put(keyPad.b3, "3.au");
    setLayout(new FlowLayout());
    add(keyPad);
    validate();
    System.out.println("Test line 1");
    String btn3 = buttonSoundNames.get(keyPad.b3);
    // will show "3.au"
    System.out.println(btn3);
  }

  public boolean action(Event e, Object arg) {
    if (e.target instanceof Button) {
      System.out.println("Test line 2");
      String name = new String((String)
buttonSoundNames.get((Button)e.target));
      System.out.println(name);
      //fails to identify the key press name
      //"1.au" or "2.au" or "3.au" is expected
      return true;
    }
    return false;
  }
}
class KeyPad extends Panel {
  Button b1,b2,b3;
  KeyPad() {
    b1 = new Button("1");
    b2 = new Button("2");
    b3 = new Button("3");
    setLayout(new GridLayout(4,3,10,10));
    add(b1);
    add(b2);
    add(b3);
  }
}