title: import command in Java
body: <p>What exactly is the difference between the following commands:</p>
  
  <pre><code>import javax.swing.JPanel;
  </code></pre>
  
  <p>and</p>
  
  <pre><code>import javax.swing.*;
  </code></pre>
  
  <p>If I use second one, compiler will import all files from swing or only the needed ones, will be any difference in size of the executable? thanks in advance</p>