@Override
    public List<String> getExtendedKeyUsage() {
        String[] extUsage = NativeCrypto.get_X509_ex_xkusage(mContext, this);
        if (extUsage == null) {
            return null;
        }

        return Arrays.asList(extUsage);
    }
An implementation of {@link X509Certificate} based on BoringSSL.
common/src/main/java/org/conscrypt/OpenSSLX509Certificate.java