title: array TextField
body: <p>Na is a parameter. I'm sure that this parameter is correct.
  I've declared an array of Na JTextField, And I would like to use one of them. But when I run my code, There is an exception...</p>
  
  <p>That's my code :</p>
  
  <pre><code>import javax.swing.JLabel;
  import javax.swing.JPanel;
  import javax.swing.JTextField;
  
  class Panneau_fenetre1A extends JPanel                      
  {   
      public Panneau_fenetre1A(int Na)
      {
          JTextField[] allField = new JTextField [Na];
          for(int i = 0;i&lt;Na;i++)
          {
              allField[i].setText(String.valueOf(0));
              allField[i].setBounds(150, 350+i*25,20, 20);
          }
      }
  
  }
  </code></pre>
  
  <p>That's the exception :</p>
  
  <pre><code>Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
      at Panneau_fenetre1A.&lt;init&gt;(Panneau_fenetre1A.java:18)
      at Cadre_fenetre1A.&lt;init&gt;(Cadre_fenetre1A.java:13)
      at Panneau_fenetre$ecout1.actionPerformed(Panneau_fenetre.java:64)
      at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2012)
      at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2335)
      at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:404)
      at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
      at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
      at java.awt.Component.processMouseEvent(Component.java:6268)
      at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
      at java.awt.Component.processEvent(Component.java:6033)
      at java.awt.Container.processEvent(Container.java:2045)
      at java.awt.Component.dispatchEventImpl(Component.java:4629)
      at java.awt.Container.dispatchEventImpl(Container.java:2103)
      at java.awt.Component.dispatchEvent(Component.java:4455)
      at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4633)
      at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4297)
      at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4227)
      at java.awt.Container.dispatchEventImpl(Container.java:2089)
      at java.awt.Window.dispatchEventImpl(Window.java:2517)
      at java.awt.Component.dispatchEvent(Component.java:4455)
      at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:649)
      at java.awt.EventQueue.access$000(EventQueue.java:96)
      at java.awt.EventQueue$1.run(EventQueue.java:608)
      at java.awt.EventQueue$1.run(EventQueue.java:606)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:105)
      at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:116)
      at java.awt.EventQueue$2.run(EventQueue.java:622)
      at java.awt.EventQueue$2.run(EventQueue.java:620)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:105)
      at java.awt.EventQueue.dispatchEvent(EventQueue.java:619)
      at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:275)
      at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:200)
      at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190)
      at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:185)
      at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:177)
  </code></pre>