src/Pure/Tools/main.scala

       GUI.dialog(null, "Isabelle", GUI.scrollable_text(Exn.message(exn)))
       system_dialog.return_code(Exn.return_code(exn, 2))
       system_dialog.join_exit
     }
 
-    def build
+    def build()
     {
       try {
         GUI.init_laf()
         Isabelle_System.init()
 

         }
       }
       catch { case exn: Throwable => exit_error(exn) }
     }
 
-    def start
+    def start()
     {
       val do_start =
       {
         try {
           /* settings directory */

         system_dialog.return_code(Exn.Interrupt.return_code)
         system_dialog.join_exit
       }
     }
 
-    build
+    build()
     val rc = system_dialog.join
-    if (rc == 0) start else sys.exit(rc)
+    if (rc == 0) start() else sys.exit(rc)
   }
 
 
 
   /** Cygwin init (e.g. after extraction via 7zip) **/