GetHTTP throws an NPE if a context service is used with only a truststore and no keystore

    private SSLContext createSSLContext(final SSLContextService service)
            throws KeyStoreException, IOException, NoSuchAlgorithmException, CertificateException, KeyManagementException, UnrecoverableKeyException {
        final KeyStore truststore = KeyStore.getInstance(service.getTrustStoreType());
        try (final InputStream in = new FileInputStream(new File(service.getTrustStoreFile()))) {
            truststore.load(in, service.getTrustStorePassword().toCharArray());
        }

        final KeyStore keystore = KeyStore.getInstance(service.getKeyStoreType());
        try (final InputStream in = new FileInputStream(new File(service.getKeyStoreFile()))) {
            keystore.load(in, service.getKeyStorePassword().toCharArray());
        }

        final SSLContext sslContext = SSLContexts.custom().loadTrustMaterial(truststore, new TrustSelfSignedStrategy()).loadKeyMaterial(keystore, service.getKeyStorePassword().toCharArray()).build();

        return sslContext;
    }