static int validatePort(int port) {
        checkArgument(isValidPort(port), "port: %s (expected: 1-65535)", port);
        return port;
    }
Raises an {@link IllegalArgumentException} if the specified {@code port} is not in the valid range.
saml/src/main/java/com/linecorp/armeria/server/saml/SamlPortConfig.java