Unable to post java file in the sidebar

I don't know if this is a bug or if I am attempting something that am trying to post a java calendar to the sidebar.   I read where Flash and Java are supported so I'm a bit confused.  This is what I'm posting:

<script type="text/javascript" src="http://cdn.widgetserver.com/syndication/subscriber/InsertWidget.js"></script><script>if (WIDGETBOX) WIDGETBOX.renderWidget('7c08c107-1b4f-41e9-97b4-dfe5277205e2');</script><noscript>Get the <a href="http://www.widgetbox.com/widget/google-calendar">Google Calendar</a> widget and many other <a href="http://www.widgetbox.com/">great free widgets</a> at <a href="http://www.widgetbox.com">Widgetbox</a>!</noscript>

I am using the Custom HTML widget option but the space is blank each time.  Am I doing something wrong or is this not supported?