If you're building applets using Microsoft's Visual J++, you might encounter problems the first time you try to run your applet outside of the development environment. Typical examples of this are:
- Your applet can't access local files (such as pictures required for animations) anymore;
- Error messages about missing classes;
- The annoying "Warning: Applet Window" message;
- Other error messages that somehow seem to be security-related.
Puzzling though this may all seem, the reason is quite simple: all applets running inside the development environment are implicitly trusted, but once you run them outside VJ++, the Java VM will start to enforce security restrictions.
To make the Microsoft VM trust your applet (and thus make it run again), you'll have to create a Cabinet (.CAB) file for the applet and digitally sign that. The tools you need for this can be found in the 'Cab&Sign' directory on your VJ++ CD-ROM, although you'll also need a certificate from a commercial certification authority (like Verisign: see www.verisign.com for more information) if you plan to distribute your applets.