### EventListener.Factory

In the preceding example we used a field, `callStartNanos`, to track the elapsed time of each event. This is handy, but it won’t work if multiple calls are executing concurrently. To accommodate this, use a `Factory` to create a new `EventListener` instance for each `Call`. This allows each listener to keep call-specific state.

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;

 * 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 {

plugins {
  kotlin("jvm")
  application
}

application {
  mainClass.set("okhttp3.sample.Crawler")
}

dependencies {
  implementation(projects.okhttp)
  implementation(libs.jsoup)
}

tasks.compileJava {
  options.isWarnings = false

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.sample;

import com.squareup.moshi.JsonAdapter;
import com.squareup.moshi.Moshi;
import com.squareup.moshi.Types;
import java.util.Collections;
import java.util.List;
import okhttp3.OkHttpClient;
import okhttp3.Request;

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.sample;

import java.io.File;
import java.io.IOException;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

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

awkward-to-reproduce situations like 500 errors or slow-loading responses.


### Example

Use MockWebServer the same way that you use mocking frameworks like
[Mockito](https://github.com/mockito/mockito):

1. Script the mocks.
2. Run application code.
3. Verify that the expected requests were made.

Here's a complete example:

```java
public void test() throws Exception {

  fun matches(header: DerHeader): Boolean

  /**
   * Returns a value from this adapter.
   *
   * This must always return a value, though it doesn't necessarily need to consume data from
   * [reader]. For example, if the reader's peeked tag isn't readable by this adapter, it may return
   * a default value.
   *
   * If this does read a value, it starts with the tag and length, and reads an entire value,