A `HttpStack` implementation for Volley that uses OkHttp as its transport.

OkHttpStack.java

import com.android.volley.toolbox.HurlStack;
import com.squareup.okhttp.OkHttpClient;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * An {@link com.android.volley.toolbox.HttpStack HttpStack} implementation which
 * uses OkHttp as its transport.
 */
public class OkHttpStack extends HurlStack {
  private final OkHttpClient client;

  public OkHttpStack() {
    this(new OkHttpClient());
  }

  public OkHttpStack(OkHttpClient client) {
    if (client == null) {
      throw new NullPointerException("Client must not be null.");
    }
    this.client = client;
  }

  @Override protected HttpURLConnection createConnection(URL url) throws IOException {
    return client.open(url);
  }   
}

client.open(url);

open method is not working,
Is there any working alternative for this?.

@sushant4anshu, yes,
That one works for me

add these libraries to gradle file
compile 'com.squareup.okhttp3:okhttp:3.9.0'
compile 'com.squareup.okhttp:okhttp-urlconnection:1.6.+'

then :

/**
* An {@link com.android.volley.toolbox.HttpStack HttpStack} implementation which
* uses OkHttp as its transport.
*/

  private class OkHttpStack extends HurlStack {
        private final OkUrlFactory mFactory;

        public OkHttpStack() {
            this(new OkHttpClient());
        }

        public OkHttpStack(OkHttpClient client) {
            if (client == null) {
                throw new NullPointerException("Client must not be null.");
            }
            mFactory = new OkUrlFactory(client);
        }

        @Override protected HttpURLConnection createConnection(URL url) throws IOException {
            return mFactory.open(url);
        }
    }

while creating Volley Queue:
mRequestQueue = Volley.newRequestQueue(mCtx.getApplicationContext(), new OkHttpStack());

What is the advantage of using OkHttp as transport for Volley?

OkUrlFactory is gone

It was deprecated in December 2015 and deleted in March 2019. You should use this instead:
https://gist.github.com/bryanstern/4e8f1cb5a8e14c202750