    public static void beforeClass() throws IOException {
        final Random r = new Random();
        for (int i = 0; i < BYTES.length; i++) {
            BYTES[i] = (byte) r.nextInt(255);
        }

        tmp = PlatformDependent.createTempFile("netty-traffic", ".tmp", null);
        tmp.deleteOnExit();
        FileOutputStream out = null;
        try {
            out = new FileOutputStream(tmp);
            out.write(BYTES);
            out.flush();
        } catch (IOException e) {
            throw new RuntimeException(e);
        } finally {
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {
                    // ignore
                }
            }
        }
    }
Opening temporary files without appropriate measures or controls can leave the file, its contents and any function that it impacts vulnerable to attack.