Compiler Warning J5020

Directive 'identifier' ignored -- extensions are turned off

The compiler detected a comment tag such as @com or @dll applied in your source code but Microsoft Language Extensions were disabled. In order to use comment tags and other Microsoft Language Extensions, the extensions option must be enabled.

! WARNING   With the Microsoft Language Extensions option disabled, any code that utilizes Microsoft Language Extensions may not work correctly.

The following example illustrates this warning:

//Microsoft Language Extensions are 'disabled'
public class Simple{
   /**@dll.import("User32")*/
   public static native int MessageBox(int hWnd, String text, String
                                       caption, int type);
   //warning: the 'MessageBox' method may not work correctly