title: Why isn't my JScrollPane with a JTextArea visible when using null LayoutManager?
body: <p>I'm trying to display a JTextArea within a JScrollPane, but I just get an empty frame when I run my (simplified) program:</p>
  
  <pre><code>import java.awt.Container;
  import java.awt.Dimension;    
  import java.awt.event.WindowAdapter;
  import java.awt.event.WindowEvent;
  
  import javax.swing.JFrame;
  import javax.swing.JScrollPane;
  import javax.swing.JTextArea;
  
  public class ScrollPaneTest extends JFrame {
      private Container myCP; 
      private JTextArea resultsTA;
      private JScrollPane scrollPane;
  
      public ScrollPaneTest() {
          setSize(500, 500);
          setLocation(100, 100);
          myCP = this.getContentPane();
          myCP.setLayout(null);
  
          resultsTA = new JTextArea("Blah blah");
          scrollPane = new JScrollPane(resultsTA,
                  JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                  JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
          scrollPane.setPreferredSize(new Dimension(200, 100));
          scrollPane.setLocation(100, 300);
          myCP.add(scrollPane);
  
          setVisible(true);
          addWindowListener(new WindowAdapter() {
              public void windowClosing(WindowEvent e) {
                  System.exit(0);
              }
          });
      }
  
      public static void main(String[] args) {
          new ScrollPaneTest();
      }
  }
  </code></pre>
  
  <p>I use the null LayoutManager to be consistent with the textbook I'm teaching from.</p>