#fixed code
                                @PostConstruct
    private void addTrayIconIfApplicable() {
        boolean isOsWindows = isOsWindows();
        if (isOsWindows) {
            logger.info("Adding windows system tray icon");
            try {
                new WindowsTrayIcon();
            } catch (HeadlessException e) {
                logger.error("Can't add a windows tray icon because running headless");
            }
        }
    }
#vulnerable code 
                                @PostConstruct
    private void addTrayIconIfApplicable() {
        String osName = System.getProperty("os.name");
        boolean isOsWindows = osName.toLowerCase().contains("windows");
        if (isOsWindows) {
            logger.info("Adding windows system tray icon");
            try {
                new WindowsTrayIcon();
            } catch (HeadlessException e) {
                logger.error("Can't add a windows tray icon because running headless");
            }
        }
    } 
                            #location 4 
                            #vulnerability type NULL_DEREFERENCE