* When making TLS connections with multiple [connection specs](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-connection-spec/), these are attempted in sequence until the TLS handshake succeeds.

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

Specific security vs. connectivity decisions are implemented by [ConnectionSpec](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-connection-spec/). OkHttp includes four built-in connection specs:

 * `RESTRICTED_TLS` is a secure configuration, intended to meet stricter compliance requirements.
 * `MODERN_TLS` is a secure configuration that connects to modern HTTPS servers.

       *
       * Android API level 26 and JVM8 both let our Error propagate directly the first time and
       * throw NoClassDefFoundError thereafter. This is the proper behavior according to the spec.
       * See https://docs.oracle.com/javase/specs/jls/se8/html/jls-12.html#jls-12.4.2 (steps #11 and
       * #5).
       *
       * Note that that "first time" might happen in a test other than
       * testLexicographicalComparatorChoice!

   * Futures#addCallback addCallback()}.
   *
   * <p>Memory consistency effects: Actions in a thread prior to adding a listener <a
   * href="https://docs.oracle.com/javase/specs/jls/se7/html/jls-17.html#jls-17.4.5">
   * <i>happen-before</i></a> its execution begins, perhaps in another thread.
   *
   * <p>Guava implementations of {@code ListenableFuture} promptly release references to listeners

## Technical Details

Just a technical detail for the curious nerds. 🤓

Underneath, in the ASGI technical specification, this is part of the <a href="https://asgi.readthedocs.io/en/latest/specs/lifespan.html" class="external-link" target="_blank">Lifespan Protocol</a>, and it defines events called `startup` and `shutdown`.

!!! info

       *
       * Android API level 26 and JVM8 both let our Error propagate directly the first time and
       * throw NoClassDefFoundError thereafter. This is the proper behavior according to the spec.
       * See https://docs.oracle.com/javase/specs/jls/se8/html/jls-12.html#jls-12.4.2 (steps #11 and
       * #5).
       *
       * Note that that "first time" might happen in a test other than
       * testLexicographicalComparatorChoice!

## Technische Details

Nur ein technisches Detail für die neugierigen Nerds. 🤓

In der technischen ASGI-Spezifikation ist dies Teil des <a href="https://asgi.readthedocs.io/en/latest/specs/lifespan.html" class="external-link" target="_blank">Lifespan Protokolls</a> und definiert Events namens `startup` und `shutdown`.

!!! info

## Detalhes técnicos

Só um detalhe técnico para nerds curiosos. 🤓

Por baixo, na especificação técnica ASGI, essa é a parte do <a href="https://asgi.readthedocs.io/en/latest/specs/lifespan.html" class="external-link" target="_blank">Protocolo Lifespan</a>, e define eventos chamados `startup` e `shutdown`.

!!! info "Informação"

          " supported protocols=${sslSocket.enabledProtocols!!.contentToString()}",
      )
  }

  /**
   * Returns a copy of this connection with the next connection spec to try, or null if no other
   * compatible connection specs are available.
   */
  internal fun nextConnectionSpec(
    connectionSpecs: List<ConnectionSpec>,
    sslSocket: SSLSocket,
  ): ConnectPlan? {

🔨 👈 👽 🔢 👈 🚫 💰 ⚛ ⚖️ 🔢 👯‍♂️ 🌅 ⚠ 👆 🔜 💪 🏪 💲 🌐 🔢 ⚖️ 🎏 🎱.

↩️ 👈, ⚫️ 🔜 👍 ↩️ ⚙️ `lifespan` 🔬 🔛.

## 📡 ℹ

📡 ℹ 😟 🤓. 👶

🔘, 🔫 📡 🔧, 👉 🍕 <a href="https://asgi.readthedocs.io/en/latest/specs/lifespan.html" class="external-link" target="_blank">🔆 🛠️</a>, &amp; ⚫️ 🔬 🎉 🤙 `startup` &amp; `shutdown`.

## 🎧 🈸