# Configuraciones y Variables de Entorno { #settings-and-environment-variables }

En muchos casos, tu aplicación podría necesitar algunas configuraciones o ajustes externos, por ejemplo, claves secretas, credenciales de base de datos, credenciales para servicios de correo electrónico, etc.

La mayoría de estas configuraciones son variables (pueden cambiar), como las URLs de bases de datos. Y muchas podrían ser sensibles, como los secretos.

        } catch (final TransportException e) {
            cleanupThread(timeout);
            throw e;
        } finally {
            /*
             * This guarantees that we leave in a valid state
             */
            st = this.state;
            if (st != 0 && st != 3 && st != 4 && st != 5 && st != 6) {
                log.error("Invalid state: " + st);
                this.state = 6;

    server.enqueue(
      MockResponse(body = "This gets leaked."),
    )
    client =
      clientTestRule
        .newClientBuilder()
        .connectionPool(ConnectionPool(0, 10, TimeUnit.MILLISECONDS))
        .build()
    val request = Request(server.url("/"))
    client.newCall(request).execute() // Ignore the response so it gets leaked then GC'd.
    awaitGarbageCollection()

          protected void doStart() {
            new Thread() {
              @Override
              public void run() {
                notifyStarted();
                // We need to wait for the main thread to leave the ServiceManager.startAsync call
                // to
                // ensure that the thread running the failure callbacks is not the main thread.
                Uninterruptibles.awaitUninterruptibly(afterStarted);

These are issues that we believe are particularly well suited for outside
contributions, often because we probably won't get to them right now. If you
decide to start on an issue, leave a comment so that other people know that
you're working on it. If you want to help out, but not alone, use the issue
comment thread to coordinate.

### Contribution guidelines and standards

        function ->> code: return stored result
    end
```

In the case of our dependency `get_settings()`, the function doesn't even take any arguments, so it always returns the same value.

That way, it behaves almost as if it was just a global variable. But as it uses a dependency function, then we can override it easily for testing.

  private static final byte[] ARRAY234 = {(byte) 2, (byte) 3, (byte) 4};

  private static final byte[] VALUES = {Byte.MIN_VALUE, -1, 0, 1, Byte.MAX_VALUE};

  // We need to test that our method behaves like the JDK method.
  @SuppressWarnings("InlineMeInliner")
  public void testHashCode() {
    for (byte value : VALUES) {
      assertThat(Bytes.hashCode(value)).isEqualTo(Byte.hashCode(value));
    }
  }

# Configurações e Variáveis de Ambiente { #settings-and-environment-variables }

Em muitos casos, sua aplicação pode precisar de configurações externas, por exemplo chaves secretas, credenciais de banco de dados, credenciais para serviços de e-mail, etc.

A maioria dessas configurações é variável (pode mudar), como URLs de banco de dados. E muitas podem ser sensíveis, como segredos.

Por esse motivo, é comum fornecê-las em variáveis de ambiente lidas pela aplicação.

 * {@linkplain #identity() identity equivalence} and the {@linkplain #equals "equals" equivalence}.
 *
 * <p><b>For users targeting Android API level 24 or higher:</b> This class will eventually
 * implement {@code BiPredicate<T, T>} (as it does in the main Guava artifact), but we currently
 * target a lower API level. In the meantime, if you have support for method references you can use
 * an equivalence as a bi-predicate like this: {@code myEquivalence::equivalent}.

    return inverse().keySet();
  }

  @Override
  final ImmutableSet<V> createValues() {
    throw new AssertionError("should never be called");
  }

  /**
   * Guaranteed to throw an exception and leave the bimap unmodified.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override