https://stackoverflow.com/questions/34293757/how-to-use-httpsurlconnection-instead-of-defaulthttpclient

private TrustManager[] getWrappedTrustManagers(TrustManager[] trustManagers) {
        final X509TrustManager originalTrustManager = (X509TrustManager) trustManagers[0];
        return new TrustManager[]{
                new X509TrustManager() {
                    public X509Certificate[] getAcceptedIssuers() {
                        return originalTrustManager.getAcceptedIssuers();
                    }

                    public void checkClientTrusted(X509Certificate[] certs, String authType) {
                        try {
                            originalTrustManager.checkClientTrusted(certs, authType);
                        } catch (CertificateException ignored) {
                        }
                    }

                    public void checkServerTrusted(X509Certificate[] certs, String authType) {
                        try {
                            originalTrustManager.checkServerTrusted(certs, authType);
                        } catch (CertificateException ignored) {
                        }
                    }
                }
        };
    }

    private SSLSocketFactory getSSLSocketFactory() {
        try {
            CertificateFactory cf = CertificateFactory.getInstance("X.509");
            InputStream caInput = getResources().openRawResource(R.raw.your_cert);
            Certificate ca = cf.generateCertificate(caInput);
            caInput.close();

            KeyStore keyStore = KeyStore.getInstance("BKS");
            keyStore.load(null, null);
            keyStore.setCertificateEntry("ca", ca);

            String tmfAlgorithm = TrustManagerFactory.getDefaultAlgorithm();
            TrustManagerFactory tmf = TrustManagerFactory.getInstance(tmfAlgorithm);
            tmf.init(keyStore);

            SSLContext sslContext = SSLContext.getInstance("TLS");
            sslContext.init(null, getWrappedTrustManagers(tmf.getTrustManagers()), null);                

            return sslContext.getSocketFactory();
        } catch (Exception e) {
            return HttpsURLConnection.getDefaultSSLSocketFactory();
        }
    }

    private class GETRequest extends AsyncTask<Void, Void, String> {
        @Override
        protected String doInBackground(Void... params) {
            try {
                URL url = new URL("https://your_server_url");
                String token = "rbkY34HnL...";
                HttpsURLConnection urlConnection = (HttpsURLConnection) url.openConnection();
                urlConnection.setSSLSocketFactory(getSSLSocketFactory());
                urlConnection.setHostnameVerifier(new HostnameVerifier() {
                    @Override
                    public boolean verify(String hostname, SSLSession session) {
//                        return true;
                        HostnameVerifier hv = HttpsURLConnection.getDefaultHostnameVerifier();
                        return hv.verify("your_domain.com", session);
                    }
                });    
                urlConnection.setRequestProperty("Authorization", "Bearer " + token);
                urlConnection.connect();
                InputStream inputStream;
                if (urlConnection.getResponseCode() != HttpURLConnection.HTTP_OK) {
                    inputStream = urlConnection.getErrorStream();
                } else {
                    inputStream = urlConnection.getInputStream();
                }
                return String.valueOf(urlConnection.getResponseCode()) + " " + urlConnection.getResponseMessage() + "\r\n" + parseStream(inputStream);
            } catch (Exception e) {
                return e.toString();
            }
        }

        @Override
        protected void onPostExecute(String response) {
            super.onPostExecute(response);
            // do something...
        }
    }

Hope it helps!