this is a regression created by a fix in 6u1 b01:
*6464971*: Need to implement webstart/plugin part of the bug fix 6439864
The code resets that handler for every app, instead of setting it up statically when plugin is initialized.
1. the following exception is shown when you load another applet with the current plugin instance
java.lang.IllegalStateException: DesktopBrowse instance has already been set.
at sun.awt.DesktopBrowse.setInstance(Unknown Source)
at sun.plugin.AppletViewer.setAppletContext(Unknown Source)
at sun.plugin.viewer.IExplorerPluginObject.<init>(Unknown Source)
at sun.plugin.viewer.IExplorerPluginContext.createPluginObject(Unknown Source)
2. Desktop.browse only works for the first applet loaded; subsequent applet calling Desktop.browse won't work, and will result in a NullPointerException.