public static String decode(String encoded) {
        Preconditions.checkNotNull(encoded, "Cannot decode null object");
        try {
            return URLDecoder.decode(encoded, CHARSET);
        } catch (UnsupportedEncodingException uee) {
            throw new OAuthException("Charset not found while decoding string: " + CHARSET, uee);
        }
    }
@Test
    public void shouldFormURLDecodeString() {
        final String encoded = "this+is+a+test+%26%5E";
        final String plain = "this is a test &^";
        assertEquals(plain, OAuthEncoder.decode(encoded));
    }