java's DO_NOTHING_ON_CLOSE
<p>I have this snippet of the code:</p>

<pre><code>public class Main_class {
    public static void main(String[] args) {

        JFrame first = new JFrame();
        first.setTitle("Hello");
        first.setSize(300, 100);
        first.setLocation(300, 100);
        first.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
        first.setVisible(true);
    }
}
</code></pre>

<p>I receive primitive frame, my question is how do I supposed to close the window without windows manager task, thanks in advance</p>
