return (Class<? extends T>) implementations.get(type);
  }

  private static final Logger logger = Logger.getLogger(ArbitraryInstances.class.getName());

  /**
   * Returns an arbitrary instance for {@code type}, or {@code null} if no arbitrary instance can be
   * determined.
   */
  public static <T> @Nullable T get(Class<T> type) {
    T defaultValue = DEFAULTS.getInstance(type);
    if (defaultValue != null) {

    ) {
    }
  }

  companion object {
    /** Arbitrary code point that's 2 bytes in UTF-8 and valid in IdnaMappingTable.txt. */
    private const val UNICODE_2 = 0x1a5

    /** Arbitrary code point that's 3 bytes in UTF-8 and valid in IdnaMappingTable.txt. */
    private const val UNICODE_3 = 0x2202

    /** Arbitrary code point that's 4 bytes in UTF-8 and valid in IdnaMappingTable.txt. */

   */
  abstract void afterRanInterruptiblyFailure(Throwable error);

  /**
   * Interrupts the running task. Because this internally calls {@link Thread#interrupt()} which can
   * in turn invoke arbitrary code it is not safe to call while holding a lock.
   */
  @SuppressWarnings("Interruption") // We are implementing a user-requested interrupt.
  final void interruptTask() {

    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // All arbitrary instances are generics-safe
    T arbitrary = (T) ArbitraryInstances.get(type.getRawType());
    if (arbitrary != null) {
      return arbitrary;
    }
    if (type.getRawType() == Class.class) {
      // If parameter is Class<? extends Foo>, we return Foo.class

    return (Class<? extends T>) implementations.get(type);
  }

  private static final Logger logger = Logger.getLogger(ArbitraryInstances.class.getName());

  /**
   * Returns an arbitrary instance for {@code type}, or {@code null} if no arbitrary instance can be
   * determined.
   */
  public static <T> @Nullable T get(Class<T> type) {
    T defaultValue = DEFAULTS.getInstance(type);
    if (defaultValue != null) {

	FormatPAX

	// FormatGNU represents the GNU header format.
	//
	// The GNU header format is older than the USTAR and PAX standards and
	// is not compatible with them. The GNU format supports
	// arbitrary file sizes, filenames of arbitrary encoding and length,
	// sparse files, and other features.
	//
	// It is recommended that PAX be chosen over GNU unless the target
	// application can only parse GNU formatted archives.
	//

    void createContext_noKerberosNoFallback_throws() throws CIFSException {
        Kerb5Authenticator auth = new Kerb5Authenticator((Subject) null);

        // Build a token with an arbitrary non-kerberos mechanism OID
        ASN1ObjectIdentifier unsupported = new ASN1ObjectIdentifier("1.2.3.4.5");
        byte[] init = spnegoInitWithMechs(unsupported);

        // Host is a FQDN to pass the short-name check

        final SmbTransport trans = SmbTransport.getSmbTransport(dc, port);
        trans.connect();
        return trans.server.encryptionKey;
    }

    /**
     * Authenticate arbitrary credentials represented by the
     * <code>NtlmPasswordAuthentication</code> object against the domain controller
     * specified by the <code>UniAddress</code> parameter. If the credentials are

        byte[] fileId = new byte[16];
        Arrays.fill(fileId, (byte) 0xCC);

        byte[] header = buildSmb2Header();
        int ctxOffsetFromHeader = 256; // arbitrary aligned location beyond header
        byte[] baseBody = buildCreateBodyWithContext(fileId, ctxOffsetFromHeader);

        // Build actual context bytes matching the pointers inside baseBody

        when(transport.disconnect(anyBoolean(), anyBoolean())).thenAnswer(inv -> {
            boolean h = inv.getArgument(0);
            boolean u = inv.getArgument(1);
            // Arbitrary behavior mapping for test purposes
            return (h && !u) || (!h && u);
        });

        boolean result = transport.disconnect(hard, inuse);

        assertEquals(expected, result);