assertNull(StringUtil.decamelize(null));
        assertEquals("EMP", StringUtil.decamelize("Emp"));
        assertEquals("AAA_BBB", StringUtil.decamelize("aaaBbb"));
        assertEquals("AAA_BBB", StringUtil.decamelize("AaaBbb"));
        assertEquals("AAA_BBB_C", StringUtil.decamelize("aaaBbbC"));
        assertEquals("USER_ID", StringUtil.decamelize("UserId"));
    }

    /**
     * @throws Exception
     */

     * <p>
     * Usage example:
     * </p>
     *
     * <pre>
     * StringUtil.decamelize("UserId")  = "USER_ID"
     * </pre>
     *
     * @param s
     *            the text
     * @return the resulting string
     */
    public static String decamelize(final String s) {
        if (s == null) {
            return null;
        }
        if (s.length() == 1) {