apache/hadoop · error · IllegalArgumentException

Address should be <host>:<port>, but it is {}

Error message

Address should be <host>:<port>, but it is {}

What it means

IllegalArgumentException from NetUtils.getPortFromHostPortString when splitting the input on ':' does not produce exactly two tokens. Anything other than a single-colon 'host:port' fails: a bare host, 'host:port:extra', empty string, or an IPv6 literal (whose colons yield many tokens). The message echoes the offending input. Note the port part is then parsed by Integer.parseInt, so a non-numeric port throws NumberFormatException instead.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/NetUtils.java:784

   * @return hort port string.
   */
  public static String getHostPortString(InetSocketAddress addr) {
    return addr.getHostName() + ":" + addr.getPort();
  }

  /**
   * Get port as integer from host port string like host:port.
   *
   * @param addr host + port string like host:port.
   * @return an integer value representing the port.
   * @throws IllegalArgumentException if the input is not in the correct format.
   */
  public static int getPortFromHostPortString(String addr)
      throws IllegalArgumentException {
    String[] hostport = addr.split(":");
    if (hostport.length != 2) {
      String errorMsg = "Address should be <host>:<port>, but it is " + addr;
      throw new IllegalArgumentException(errorMsg);
    }
    return Integer.parseInt(hostport[1]);
  }
  
  /**
   * Checks if {@code host} is a local host name and return {@link InetAddress}
   * corresponding to that address.
   * 
   * @param host the specified host
   * @return a valid local {@link InetAddress} or null
   * @throws SocketException if an I/O error occurs
   */
  public static InetAddress getLocalInetAddress(String host)
      throws SocketException {
    if (host == null) {
      return null;
    }
    InetAddress addr = null;

View on GitHub (pinned to 2add963021)

Solutions

1. Pass exactly 'host:port' — strip any 'scheme://' prefix first
2. For IPv6, use a URI-based parse (URI.create("dummyscheme://[::1]:8080").getPort()) instead of this helper
3. Pre-check with addr.split(":").length == 2 (and a numeric last token) before calling, to give a clearer error

Example fix

// before
int port = NetUtils.getPortFromHostPortString("http://host:8080"); // 3 tokens -> IllegalArgumentException

// after
String hp = "http://host:8080".replaceFirst("^\\w+://", ""); // "host:8080"
int port = NetUtils.getPortFromHostPortString(hp);

String[] parts = addr.split(":");
if (parts.length != 2 || !parts[1].matches("\\d+")) {
  throw new IllegalStateException("expected host:port, got: " + addr);
}

static boolean isHostPort(String addr) {
  String[] p = addr.split(":");
  return p.length == 2 && p[1].matches("\\d+");
}

When it happens

Trigger: getPortFromHostPortString("myhost") (no port); getPortFromHostPortString("http://myhost:8080") (scheme adds a colon); getPortFromHostPortString("::1:8080") or any unbracketed IPv6 address.

Common situations: Passing URLs where a host:port is expected; forgetting to strip the scheme; IPv6 addresses not bracketed (even bracketed '[::1]:8080' fails because split(':') sees 3+ tokens — this helper is effectively IPv4/hostname only).

Related errors

• Wrong length: {digest.length}
• Wrong length: {hex.length}
• Not a hex character: {c}
• No schema options are provided
• No codec option is provided

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/44b34c106b386dcb. Report an issue: GitHub.