// Test fallback logic
        assertTrue(errorHandler.shouldFallbackToTcp(hardwareError), "Hardware errors should suggest TCP fallback");
        assertFalse(errorHandler.shouldFallbackToTcp(timeoutError), "Timeout errors should not immediately suggest TCP fallback");

        // Test error classification using public API

      Function<? super Throwable, ? extends V> fallback,
      Executor executor) {
    return AbstractCatchingFuture.create(input, exceptionType, fallback, executor);
  }

  public static <V extends @Nullable Object> ListenableFuture<V> catchingAsync(
      ListenableFuture<? extends V> input,
      Class<Throwable> exceptionType,
      AsyncFunction<? super Throwable, ? extends V> fallback,
      Executor executor) {

     * Execute a callable through the circuit breaker with fallback
     *
     * @param <T> return type
     * @param callable the callable to execute
     * @param fallback fallback supplier if circuit is open
     * @return the result or fallback value
     * @throws Exception if execution fails and no fallback provided
     */
    public <T> T call(Callable<T> callable, Callable<T> fallback) throws Exception {

     * potential NTLM fallback (if the server does not support kerberos).
     *
     * @param subject
     *            represents the user who perform Kerberos authentication. Should at least contain a TGT for the user.
     * @param domain
     *            domain for NTLM fallback
     * @param username
     *            user for NTLM fallback
     * @param password

   *
   * @param future The future attach the callback to.
   * @param callback The callback to invoke when {@code future} is completed.
   * @param executor The executor to run {@code callback} when the future completes.
   * @since 10.0
   */
  public static <V extends @Nullable Object> void addCallback(
      ListenableFuture<V> future, FutureCallback<? super V> callback, Executor executor) {

    }

    @Test
    @DisplayName("Test fallback used when circuit is open")
    void testFallbackWhenOpen() throws Exception {
        // Open the circuit
        circuitBreaker.tripBreaker();

        String result = circuitBreaker.call(() -> "primary", () -> "fallback");

        assertEquals("fallback", result);
    }

    @Test

import java.util.EnumSet;
import java.util.Set;

/**
 * Interface for RDMA provider implementations.
 *
 * This interface abstracts different RDMA implementations such as
 * InfiniBand, iWARP, RoCE, or TCP fallback providers.
 */
public interface RdmaProvider {

    /**
     * Check if RDMA is available on this system
     *
     * @return true if RDMA can be used, false otherwise
     */
    boolean isAvailable();

 */
package okhttp3.internal

import java.net.InetAddress
import okhttp3.Dns

/**
 * A network that always resolves two IP addresses per host. Use this when testing route selection
 * fallbacks to guarantee that a fallback address is available.
 */
class DoubleInetAddressDns : Dns {
  override fun lookup(hostname: String): List<InetAddress> {
    val addresses = Dns.SYSTEM.lookup(hostname)

 *
 * @author Kevin Damm
 * @author Kyle Maddison
 */
final class LittleEndianByteArray {

  /**
   * The instance that actually does the work; delegates to VarHandle, Unsafe, or a Java-8
   * compatible pure-Java fallback.
   */
  private static final LittleEndianBytes byteArray = makeGetter();

  /**
   * Load 8 bytes into long in a little endian manner, from the substring between position and

        assertTrue(ex.getMessage().contains("Cannot use netbios/short names"));
    }

    @Test
    @DisplayName("createContext: no Kerberos in initial token and no fallback -> throws")
    void createContext_noKerberosNoFallback_throws() throws CIFSException {
        Kerb5Authenticator auth = new Kerb5Authenticator((Subject) null);