### 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 {
  // Create a MockWebServer. These are lean enough that you can create a new
  // instance for every unit test.

  for (i in 0 until length) {
    val c = this[i]
    // The WHATWG Host parsing rules accepts some character codes which are invalid by
    // definition for OkHttp's host header checks (and the WHATWG Host syntax definition). Here
    // we rule out characters that would cause problems in host headers.
    if (c <= '\u001f' || c >= '\u007f') {
      return true
    }
    // Check for the characters mentioned in the WHATWG Host parsing spec:

![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

**This release fixes a severe bug where OkHttp incorrectly detected and recovered from unhealthy
connections.** Stale or canceled connections were incorrectly attempted when they shouldn't have
been, leading to rare cases of infinite retries. Please upgrade to this release!

 *  Fix: don't return stale DNS entries in `DnsOverHttps`. We were caching DNS results indefinitely
    rather than the duration specified in the response's cache-control header.

    var b = 0
    for (codePoint in input) {
      if (codePoint < INITIAL_N) {
        result.writeByte(codePoint)
        b++
      }
    }

    // Copy a delimiter if any basic code points were emitted.
    if (b > 0) result.writeByte('-'.code)

    var n = INITIAL_N
    var delta = 0
    var bias = INITIAL_BIAS
    var h = b
    while (h < input.size) {

  }

  @Test
  fun connectViaHttpProxyToHttpsUsingHttpsProxySystemProperty() {
    testConnectViaHttpProxyToHttps(ProxyConfig.HTTPS_PROXY_SYSTEM_PROPERTY)
  }

  /**
   * We were verifying the wrong hostname when connecting to an HTTPS site through a proxy.
   * http://b/3097277
   */
  private fun testConnectViaHttpProxyToHttps(proxyConfig: ProxyConfig) {

/**
 * Runs MockWebServer for the duration of a single test method.
 *
 * Specifically while junit instances passes into test constructor
 * are typically shares amongst all tests, a fresh instance will be
 * received here. Use with @BeforeAll and @AfterAll, is not supported.
 *
 * There are 3 ids for instances
 * - The test instance default (passed into constructor)

   * mutated by the call thread only. If is accessed by background connect threads.
   */
  private val tcpConnectsInFlight = CopyOnWriteArrayList<Plan>()

  /**
   * Results are posted here as they occur. The find job is done when either one plan completes
   * successfully or all plans fail.
   */
  private val connectResults = taskRunner.backend.decorate(LinkedBlockingDeque<ConnectResult>())

      arrayOf(
        TlsVersion.TLS_1_2,
        TlsVersion.TLS_1_1,
        TlsVersion.TLS_1_0,
      )
    var socket = createSocketWithEnabledProtocols(*enabledSocketTlsVersions)

    // MODERN_TLS is used here.
    val attempt0 =
      routePlanner.planConnectToRoute(route)
        .planWithCurrentOrInitialConnectionSpec(connectionSpecs, socket)
    assertThat(attempt0.isTlsFallback).isFalse()

  private fun buildServerSslSocketFactory(): SSLSocketFactory {
    // The test uses JDK default SSL Context instead of the Platform provided one
    // as Conscrypt seems to have some differences, we only want to test client side here.
    return try {
      val keyManager =
        newKeyManager(
          null,
          serverCert,
          serverIntermediateCa.certificate,
        )
      val trustManager =