Rest Android security technology choice [closed]

Iam building Webservice (using J2EE) along with an android Client. now Iam facing with which security technology to choose? and integrate it with my Rest services. I crawled google and suggestion are about Oauth2.0, Basic authentication using TLS, api key. In my android application used HttpClient i dont if integration one of these solution will require great changes in my code. By this occasion can anyone could make me a great description of the two first ones with suggestion of best tutorials with example ....

public class DataLoader {
DefaultHttpClient sslClient;
private boolean silent;

public class CustomX509TrustManager implements X509TrustManager {

    @Override
    public void checkClientTrusted(X509Certificate[] chain, String authType)
            throws CertificateException {
    }

    @Override
    public void checkServerTrusted(
            java.security.cert.X509Certificate[] certs, String authType)
            throws CertificateException {
    }

    public X509Certificate[] getAcceptedIssuers() {
        return null;
    }
}

public class CustomSSLSocketFactory extends SSLSocketFactory {
    SSLContext sslContext = SSLContext.getInstance("TLS");

    public CustomSSLSocketFactory(KeyStore truststore)
            throws NoSuchAlgorithmException, KeyManagementException,
            KeyStoreException, UnrecoverableKeyException {
        super(truststore);
        TrustManager tm = new CustomX509TrustManager();
        sslContext.init(null, new TrustManager[] { tm }, null);
    }

    public CustomSSLSocketFactory(SSLContext context)
            throws KeyManagementException, NoSuchAlgorithmException,
            KeyStoreException, UnrecoverableKeyException {
        super(null);
        sslContext = context;
    }

    @Override
    public Socket createSocket(Socket socket, String host, int port,
            boolean autoClose) throws IOException, UnknownHostException {
        return sslContext.getSocketFactory().createSocket(socket, host,
                port, autoClose);
    }

    @Override
    public Socket createSocket() throws IOException {
        return sslContext.getSocketFactory().createSocket();
    }
}

public HttpResponse execute(HttpUriRequest request) {
    if (!(silent)) {
        Log.i("Performing request", "Performing request");
        for (Header header : request.getAllHeaders())
            Log
                                                    

                                                                                                                
                                                        
                                                    
                                                    



                                                        

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