getSSLConfig.java

 private static SSLContext getSSLConfig(Context context) throws CertificateException, IOException,
      KeyStoreException, NoSuchAlgorithmException, KeyManagementException {

    // Loading CAs from an InputStream
    CertificateFactory cf = null;
    cf = CertificateFactory.getInstance("X.509");

    Certificate ca;
    // I'm using Java7. If you used Java6 close it manually with finally.
    try (InputStream cert = context.getResources().openRawResource(R.raw.nginxselfsigned)) {
      ca = cf.generateCertificate(cert);
    }

    // Creating a KeyStore containing our trusted CAs
    String keyStoreType = KeyStore.getDefaultType();
    KeyStore keyStore = KeyStore.getInstance(keyStoreType);
    keyStore.load(null, null);
    keyStore.setCertificateEntry("ca", ca);

    // Creating a TrustManager that trusts the CAs in our KeyStore.
    String tmfAlgorithm = TrustManagerFactory.getDefaultAlgorithm();
    TrustManagerFactory tmf = TrustManagerFactory.getInstance(tmfAlgorithm);
    tmf.init(keyStore);

    // Creating an SSLSocketFactory that uses our TrustManager
    SSLContext sslContext = SSLContext.getInstance("TLS");
    sslContext.init(null, tmf.getTrustManagers(), null);

    return sslContext;
  }