![Events Diagram](../assets/images/******@****.***)

Here’s a [sample event listener](https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PrintEventsNonConcurrent.java) that prints each event with a timestamp.

```java

import java.io.IOException;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

/**
 * Simple test adaptable to show a failure in older versions of OkHttp
 * or Android SDKs.
 */
@RunWith(AndroidJUnit4.class)
public class IssueReproductionTest {
  @Test public void getFailsWithoutAdditionalCert() throws IOException {

import javax.net.ssl.SSLSocket
import okhttp3.Protocol
import okhttp3.internal.platform.BouncyCastlePlatform
import okhttp3.internal.platform.Platform
import org.bouncycastle.jsse.BCSSLSocket

/**
 * Simple non-reflection SocketAdapter for BouncyCastle.
 */
class BouncyCastleSocketAdapter : SocketAdapter {
  override fun matchesSocket(sslSocket: SSLSocket): Boolean = sslSocket is BCSSLSocket

package okhttp3.sample;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.security.GeneralSecurityException;
import java.security.KeyStore;
import java.security.SecureRandom;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManagerFactory;
import okhttp3.mockwebserver.Dispatcher;

 * interfere with session-based authentication schemes that require cookies.
 *
 * As persistence, implementations of this interface must also provide storage of cookies. Simple
 * implementations may store cookies in memory; sophisticated ones may use the file system or
 * database to hold accepted cookies. The [cookie storage model][rfc_6265_53] specifies policies for
 * updating and expiring cookies.

 * it easy to get sample values to use in such tests.
 *
 * This class is pretty fast and loose with default values: it attempts to provide values that are
 * well-formed, but doesn't guarantee values are internally consistent. Callers must take care to
 * configure the factory when sample values impact the correctness of the test.
 */
class TestValueFactory : Closeable {

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.curl

import kotlin.test.Test

class OkcurlTest {
  @Test
  fun simple() {
    Main().main(listOf("--help"))
  }

    val certificatePinner =
      CertificatePinner.Builder()
        .add("**.example.com", certA1Sha256Pin)
        .build()

    assertThat(certificatePinner.findMatchingPins("xample.com")).isEmpty()
    assertThat(certificatePinner.findMatchingPins("dexample.com")).isEmpty()
    assertThat(certificatePinner.findMatchingPins("barnexample.com")).isEmpty()
  }

   capacity and competence.

 * **Be considerate**: People use our work, and we depend on the work of others. Consider users and
   colleagues before taking action. For example, changes to code, infrastructure, policy, and
   documentation may negatively impact others.

 * **Be respectful**: We expect people to work together to resolve conflict, assume good intentions,

# Calls

The HTTP client’s job is to accept your request and produce its response. This is simple in theory but it gets tricky in practice.

## [Requests](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-request/)

Each HTTP request contains a URL, a method (like `GET` or `POST`), and a list of headers. Requests may also contain a body: a data stream of a specific content type.

## [Responses](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-response/)