public static String hex(final int codepoint) {
        return Integer.toHexString(codepoint).toUpperCase(Locale.ENGLISH);
    }
<p>Returns an upper case hexadecimal <code>String</code> for the given
character.</p>

@param codepoint The codepoint to convert.
@return An upper case hexadecimal <code>String</code>
replugin-host-library/replugin-host-lib/src/main/java/com/qihoo360/replugin/ext/parser/utils/xml/CharSequenceTranslator.java