title: Java applet cached forever, not downloading new version?
body: <p>We have a case where clients seem to be eternally caching versions of applets.  We're making use of the <code>&lt;param name="cache_version"&gt;</code> tag correctly within our <code>&lt;object&gt;</code> tag, or so we think.  We went from a version string of <code>7.1.0.40</code> to <code>7.1.0.42</code> and this triggered a download for only about half of our clients.</p>
  
  <p>It doesn't seem to matter which version of the JRE the client is running.  We've seen people have this problem on 1.4, 1.5 and 1.6.</p>
  
  <p>Does anybody have experience with explicit cache versions?  Does it work more reliably (ignoring speed) to instead rely on the <code>cache_archive</code>'s "Last-Modified" and/or "Content-Length" values (as per <a href="http://java.sun.com/j2se/1.4.2/docs/guide/plugin/developer_guide/applet_caching.html" rel="noreferrer">Sun's Site</a>)?</p>
  
  <p>FYI, object block looks like this:</p>
  
  <pre><code>&lt;object&gt;
    &lt;param name="ARCHIVE" value="foo.jar"&gt;
    &lt;param name="CODE" value="com.foo.class"&gt;
    &lt;param name="CODEBASE" value="."&gt;
    &lt;param name="cache_archive" value="foo.jar"&gt;
    &lt;param name="cache_version" value="7.1.0.40"&gt;
    &lt;param name="NAME" value="FooApplet"&gt;
    &lt;param name="type" value="application/x-java-applet;jpi-version=1.4.2_13"&gt;
    &lt;param name="scriptable" value="true"&gt;
    &lt;param name="progressbar" value="true"/&gt;
    &lt;param name="boxmessage" value="Loading Web Worksheet Applet..."/&gt;
  &lt;/object&gt;
  </code></pre>