server.sink.write("0a00".decodeHex()).emit() // Invalid non-final ping frame.
    client.processNextFrame() // Detects error, send close, close connection.
    taskFaker.runTasks()
    client.webSocket!!.finishReader()
    assertThat(client.closed).isTrue()
    client.listener.assertFailure(
      ProtocolException::class.java,
      "Control frames must be final.",
    )
    server.processNextFrame()
    taskFaker.runTasks()

```
testImplementation("com.squareup.okhttp3:mockwebserver3-junit4:4.12.0")
```

Then in tests annotated `@org.junit.Test`, you may declare a field with the `@Rule` annotation:

```
@Rule public final MockWebServerRule serverRule = new MockWebServerRule();
```

The `serverRule` field has a `server` field. It is an instance of `MockWebServer`. That instance
will be shut down automatically after the test runs.

 *
 * In Java JUnit 4 tests (ie. tests annotated `@org.junit.Test`), use this by defining a field with
 * the `@Rule` annotation:
 *
 * ```java
 * @Rule public final MockWebServerRule serverRule = new MockWebServerRule();
 * ```
 *
 * For Kotlin the `@JvmField` annotation is also necessary:
 *
 * ```kotlin
 * @JvmField @Rule val serverRule = MockWebServerRule()
 * ```
 */

	public final fun immutable ()Z
	public final fun isPrivate ()Z
	public final fun isPublic ()Z
	public final fun maxAgeSeconds ()I
	public final fun maxStaleSeconds ()I
	public final fun minFreshSeconds ()I
	public final fun mustRevalidate ()Z
	public final fun noCache ()Z
	public final fun noStore ()Z
	public final fun noTransform ()Z
	public final fun onlyIfCached ()Z

	public final fun noClientAuth ()V
	public final fun protocols ()Ljava/util/List;
	public final fun requestClientAuth ()V
	public final fun requireClientAuth ()V
	public final fun setBodyLimit (J)V
	public final fun setDispatcher (Lokhttp3/mockwebserver/Dispatcher;)V
	public final fun setProtocolNegotiationEnabled (Z)V
	public final fun setProtocols (Ljava/util/List;)V

}

public final class okhttp3/sse/EventSources {
	public static final field INSTANCE Lokhttp3/sse/EventSources;
	public static final fun createFactory (Lokhttp3/Call$Factory;)Lokhttp3/sse/EventSource$Factory;
	public static final synthetic fun createFactory (Lokhttp3/OkHttpClient;)Lokhttp3/sse/EventSource$Factory;
	public static final fun processResponse (Lokhttp3/Response;Lokhttp3/sse/EventSourceListener;)V

    assertFailsWith<ProtocolException> {
      clientReader.processNextFrame()
    }.also { expected ->
      assertThat(expected.message)
        .isEqualTo("Control frames must be final.")
    }
  }

  @Test fun reservedFlag1IsUnsupportedWithNoCompression() {
    data.write("ca00".decodeHex()) // Empty pong, flag 1 set.
    assertFailsWith<ProtocolException> {
      clientReader.processNextFrame()

import okhttp3.Interceptor;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public final class CheckHandshake {
  /** Rejects otherwise-trusted certificates. */
  private static final Interceptor CHECK_HANDSHAKE_INTERCEPTOR = new Interceptor() {
    final Set<String> denylist = Collections.singleton(
        "sha256/afwiKY3RxoMmLkuRW1l7QsPZTJPwDS2pdDROQjXw8ig=");

import java.util.concurrent.TimeUnit;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okhttp3.WebSocket;
import okhttp3.WebSocketListener;
import okio.ByteString;

public final class WebSocketEcho extends WebSocketListener {
  private void run() {
    OkHttpClient client = new OkHttpClient.Builder()
        .readTimeout(0,  TimeUnit.MILLISECONDS)
        .build();

    return response.body().string();
  }
}
```


Post to a Server
----------------

This program posts data to a service. [Full source][post_example].

```java
public static final MediaType JSON = MediaType.get("application/json");

OkHttpClient client = new OkHttpClient();

String post(String url, String json) throws IOException {
  RequestBody body = RequestBody.create(json, JSON);