assertFailsToDecode(base64(), "Wf2!", "Unrecognized character: !");
    // This sentence just isn't base64() encoded.
    assertFailsToDecode(base64(), "let's not talk of love or chains!");
    // A 4n+1 length string is never legal base64().
    assertFailsToDecode(base64(), "12345", "Invalid input length 5");
    // These have a combination of invalid length, unrecognized characters and wrong padding.

  /**
   * Returns the tag attached with `Object.class` as a key, or null if no tag is attached with
   * that key.
   *
   * Prior to OkHttp 3.11, this method never returned null if no tag was attached. Instead it
   * returned either this request, or the request upon which this request was derived with
   * [newBuilder].
   *

    manager.awaitStopped(5, SECONDS); // no exception thrown
  }

  /**
   * This covers a case where if the last service to stop failed then the stopped callback would
   * never be called.
   */
  public void testSingleFailedServiceCallsStopped() {
    Service a = new FailStartService();
    ServiceManager manager = new ServiceManager(asList(a));

            if (longValue > Integer.MAX_VALUE) {
                return null;
            }
            return (int) longValue;
        } catch (NumberFormatException e) {
            // should never happen since checked isDigits(s) before
            return null;
        }
    }

    @Override
    public String toString() {
        return comparable.toString();
    }

   * except {@link Object#equals}, {@link Object#hashCode} and {@link Object#toString}. The result
   * will be returned as the proxied method's return value.
   *
   * <p>Unlike {@link #invoke}, {@code args} will never be null. When the method has no parameter,
   * an empty array is passed in.
   */
  protected abstract @Nullable Object handleInvocation(
      Object proxy, Method method, @Nullable Object[] args) throws Throwable;

    * An example is `404`, for a "Not Found" response.
    * For generic errors from the client, you can just use `400`.
* `500 - 599` are for server errors. You almost never use them directly. When something goes wrong at some part in your application code, or server, it will automatically return one of these status codes.

/// tip

import java.util.Iterator;
import java.util.List;
import java.util.RandomAccess;
import java.util.stream.Collector;
import org.jspecify.annotations.Nullable;

/**
 * A {@link List} whose contents will never change, with many other important properties detailed at
 * {@link ImmutableCollection}.
 *
 * <p>See the Guava User Guide article on <a href=

 * part of the open-source <a href="https://github.com/google/guava">Guava</a> library.
 *
 * <p>The classes in this package include:
 *
 * <h2>Immutable collections</h2>
 *
 * These are collections whose contents will never change. They also offer a few additional
 * guarantees (see {@link ImmutableCollection} for details). Implementations are available for both
 * the JDK collection types and the Guava collection types (listed below).
 *

    @Override
    protected List<V> delegate() {
      return emptyList();
    }
  }

  @Override
  Iterator<Entry<K, V>> entryIterator() {
    throw new AssertionError("should never be called");
  }

  @Override
  Collection<Entry<K, V>> createEntries() {
    return new Entries();
  }

  @WeakOuter
  class Entries extends ForwardingCollection<Entry<K, V>> {
    @Override

    @Override
    protected List<V> delegate() {
      return emptyList();
    }
  }

  @Override
  Iterator<Entry<K, V>> entryIterator() {
    throw new AssertionError("should never be called");
  }

  @Override
  Collection<Entry<K, V>> createEntries() {
    return new Entries();
  }

  @WeakOuter
  class Entries extends ForwardingCollection<Entry<K, V>> {
    @Override