import netscape.security.PrivilegeManager;
import netscape.security.ForbiddenTargetException;
...
try
   {
   if ( inNetscape )
      {
      PrivilegeManager.enablePrivilege( "30Capabilities" );
      PrivilegeManager.enablePrivilege( "UniversalConnect" );
      PrivilegeManager.enablePrivilege( "UniversalListen" );
      PrivilegeManager.enablePrivilege( "UniversalLinkAccess" );
      PrivilegeManager.enablePrivilege( "UniversalThreadAccess" );
      }
   }
catch ( ForbiddenTargetException e )
   {
   System.out.println( "Cannot continue without permission." );
   }