The javadoc says:

        /**
         * Returns an instance of {@link Logger Logger}
         * for the given {@code caller}.
         *
         * @param name the name of the logger.
         * @param caller the class for which the logger is being requested;
         *               can be {@code null}.
         *
         * @return a {@link Logger logger} suitable for the given caller's
         *         use.
         * @throws NullPointerException if {@code name} is {@code null} or
         *        {@code caller} is {@code null}.
         * @throws SecurityException if a security manager is present and its
         *         {@code checkPermission} method doesn't allow the
         *         {@code RuntimePermission("loggerFinder")}.
         */
        public abstract Logger getLogger(String name, /* Module */ Class<?> caller);

@throws NullPointerException  is correct; 'can be null' must be removed from @param caller.