// Apply withDefaultPort(), yielding hp2.
    final boolean badDefaultPort = (defaultPort < 0 || defaultPort > 65535);
    HostAndPort hp2 = null;
    try {
      hp2 = hp.withDefaultPort(defaultPort);
      assertFalse(badDefaultPort);
    } catch (IllegalArgumentException e) {
      assertTrue(badDefaultPort);
    }

    // Check the pre-withDefaultPort() instance.
    if (expectHasExplicitPort) {

import javax.annotation.CheckForNull;

/**
 * An immutable representation of a host and port.
 *
 * <p>Example usage:
 *
 * <pre>
 * HostAndPort hp = HostAndPort.fromString("[2001:db8::1]")
 *     .withDefaultPort(80)
 *     .requireBracketsForIPv6();
 * hp.getHost();   // returns "2001:db8::1"
 * hp.getPort();   // returns 80
 * hp.toString();  // returns "[2001:db8::1]:80"
 * </pre>
 *