if (startBracket != -1 && endBracket != -1 && endBracket > startBracket) {
            return transportStr.substring(startBracket + 1, endBracket);
        }
        // Fallback: just use address
        return transport.getRemoteAddress().getHostAddress();
    }

    /**
     * Get connection key from address and port
     */

            final Instant instant = Instant.from(RFC_1123_FORMATTER.parse(value));
            return Date.from(instant);
        } catch (final DateTimeParseException e) {
            // Try fallback
        }
        // Fallback to custom pattern for non-standard formats (e.g., single-digit day)
        try {
            return DATE_FORMAT_HOLDER.get().parse(value);
        } catch (final ParseException e) {

            if (entry.getInconsistencyCount() > 5) {
                entry.invalidate();
            }
        }
    }
}
```

### 9.2 Fallback Mechanisms
```java
public class DirectoryOperationFallback {
    public SmbFile[] safeListFiles(SmbFile directory) throws IOException {
        try {
            // Try cached listing first

		return policies, nil
	}

	if userPolicyPresent {
		// if user mapping present and no group policies found
		// rely on user policy for access, instead of fallback.
		return nil, nil
	}

	var mu sync.Mutex

	// no mappings found, fallback for all groups.
	g := errgroup.WithNErrs(len(groups)).WithConcurrency(10) // load like 10 groups at a time.

	for index := range groups {
		g.Go(func() error {

				if split := strings.Split(string(b64), "x"); len(split) == 2 {
					t, err := strconv.ParseInt(split[1], 10, 64)
					if err == nil {
						modTime = time.Unix(0, t)
					}
				}
			}
			// Fallback for older uploads without time in the ID.
			if modTime.IsZero() {
				wait := deleteMultipartCleanupSleeper.Timer(ctx)
				fi, err := disk.ReadVersion(ctx, "", minioMetaMultipartBucket, uploadIDPath, "", ReadOptions{})

         * Login with no credentials
         */
        NULL,
        /**
         * Guest authentication
         *
         * Allows login with invalid credentials (username and/or password)
         * Fallback to anonymous authentication is permitted
         */
        GUEST,
        /**
         * Regular user authentication
         */
        USER
    }

                org.dbflute.helper.jprop.JavaPropertiesResult result = reader.read();
                propField.set(this, result);
            } catch (Exception e) {
                // Fallback: ignore initialization errors since we override methods anyway
            }
        }
    }

        return getSystemPropertyAsInt(Constants.LTR_WINDOW_SIZE_PROPERTY, 100);
    }

    /**
     * Gets the permission fields for Entra ID authentication.
     * Uses new entraid.permission.fields key with fallback to legacy aad.permission.fields.
     * @return Array of permission field names.
     */
    default String[] getEntraIdPermissionFields() {
        String value = getSystemProperty("entraid.permission.fields", null);

            final byte[] adjustedNonce;
            if (nonce.length == 12) {
                adjustedNonce = nonce;
            } else {
                // Fallback for compatibility
                adjustedNonce = new byte[12];
                System.arraycopy(nonce, 0, adjustedNonce, 0, Math.min(12, nonce.length));
            }

          // Some Android 5.0.x Samsung devices have bugs in JDK reflection APIs that cause
          // getDeclaredField to throw a NoSuchFieldException when the field is definitely there.
          // For these users fallback to a suboptimal implementation, based on synchronized. This
          // will be a definite performance hit to those users.
          thrownAtomicReferenceFieldUpdaterFailure = atomicReferenceFieldUpdaterFailure;