Program: 104247
Project: 104247
Buggy source:
/** 
 * Handles the <tt>ActionEvent</tt> generated when user presses one of the buttons in this panel.
 */
public void actionPerformed(ActionEvent evt){
  JButton button=(JButton)evt.getSource();
  String buttonName=button.getName();
  if (buttonName.equals(CALL_BUTTON)) {
    if (isCallMetaContact) {
      Object[] selectedContacts=mainFrame.getContactListPanel().getContactList().getSelectedValues();
      java.util.List<Contact> telephonyContacts=new Vector<Contact>();
      for (int i=0; i < selectedContacts.length; i++) {
        Object o=selectedContacts[i];
        if (o instanceof MetaContact) {
          Contact contact=((MetaContact)o).getDefaultContact(OperationSetBasicTelephony.class);
          if (contact != null)           telephonyContacts.add(contact);
 else {
            new ErrorDialog(this.mainFrame,GuiActivator.getResources().getI18NString("String_Node_Str"),GuiActivator.getResources().getI18NString("String_Node_Str",new String[]{((MetaContact)o).getDisplayName()})).showDialog();
          }
        }
      }
      if (telephonyContacts.size() > 0)       CallManager.createCall(protocolProvider,telephonyContacts);
    }
 else     if (!phoneNumberCombo.isComboFieldEmpty()) {
      String stringContact=phoneNumberCombo.getEditor().getItem().toString();
      CallManager.createCall(protocolProvider,stringContact);
    }
  }
 else   if (buttonName.equals(DIAL_BUTTON)) {
    if (!dialpadDialog.isVisible()) {
      dialpadDialog.setSize(mainFrame.getWidth() - 20,dialpadDialog.getHeight());
      dialpadDialog.setLocation(mainFrame.getX() + 10,dialButton.getLocationOnScreen().y - dialpadDialog.getHeight());
      dialpadDialog.setVisible(true);
    }
 else {
      dialpadDialog.setVisible(false);
    }
  }
}

Fixed version (ground truth):
/** 
 * Handles the <tt>ActionEvent</tt> generated when user presses one of the buttons in this panel.
 */
public void actionPerformed(ActionEvent evt){
  JButton button=(JButton)evt.getSource();
  String buttonName=button.getName();
  if (buttonName.equals(CALL_BUTTON)) {
    if (isCallMetaContact) {
      Object[] selectedContacts=mainFrame.getContactListPanel().getContactList().getSelectedValues();
      java.util.List<Contact> telephonyContacts=new Vector<Contact>();
      for (int i=0; i < selectedContacts.length; i++) {
        Object o=selectedContacts[i];
        if (o instanceof MetaContact) {
          Contact contact=((MetaContact)o).getDefaultContact(OperationSetBasicTelephony.class);
          if (contact != null)           telephonyContacts.add(contact);
 else {
            new ErrorDialog(this.mainFrame,GuiActivator.getResources().getI18NString("String_Node_Str"),GuiActivator.getResources().getI18NString("String_Node_Str",new String[]{((MetaContact)o).getDisplayName()})).showDialog();
          }
        }
      }
      if (telephonyContacts.size() > 0)       CallManager.createCall(protocolProvider,telephonyContacts);
    }
 else     if (!phoneNumberCombo.isComboFieldEmpty()) {
      String stringContact=phoneNumberCombo.getEditor().getItem().toString();
      CallManager.createCall(protocolProvider,stringContact);
    }
  }
 else   if (buttonName.equals(DIAL_BUTTON)) {
    if (!dialpadDialog.isVisible()) {
      dialpadDialog.setSize(mainFrame.getWidth() - 20,dialpadDialog.getHeight());
      dialpadDialog.setLocation(mainFrame.getX() + 10,button.getLocationOnScreen().y - dialpadDialog.getHeight());
      dialpadDialog.setVisible(true);
    }
 else {
      dialpadDialog.setVisible(false);
    }
  }
}