TooTallNate/Java-WebSocket · error · InvalidHandshakeException

Invalid status line received

Error message

Invalid status line received: %s Status line: %s

What it means

This guard fires in Draft.translateHandshakeHttpServer when the third token of the request's first line is not 'HTTP/1.1'. The WebSocket handshake (RFC 6455) requires HTTP/1.1; a request line ending in HTTP/1.0 or any other protocol token cannot carry the required upgrade semantics, so the handshake is rejected with InvalidHandshakeException. The faulty input is a client request whose status line declares a protocol/version other than HTTP/1.1.

Solutions

1. Ensure the connecting client uses HTTP/1.1 for the upgrade request (WebSocket requires it, not HTTP/1.0)
2. Check for old HTTP client libraries, embedded devices, or proxies downgrading the request to HTTP/1.0
3. Verify the request line is well formed with exactly three tokens: METHOD resource HTTP/1.1
4. If supporting legacy clients is required, upgrade them or terminate the connection gracefully at the plain-HTTP layer instead

When it happens

Trigger: Thrown at src/main/java/org/java_websocket/drafts/Draft.java:149 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of TooTallNate/Java-WebSocket@afeacbf8c0 (2026-09-09). Data as JSON: /api/errors/7fd2a28322afb281. Report an issue: GitHub.

Appendix: source

Thrown at src/main/java/org/java_websocket/drafts/Draft.java:149

    return handshake;
  }

  /**
   * Checking the handshake for the role as server
   *
   * @param firstLineTokens the token of the first line split as as an string array
   * @param line            the whole line
   * @return a handshake
   */
  private static HandshakeBuilder translateHandshakeHttpServer(String[] firstLineTokens,
      String line) throws InvalidHandshakeException {
    // translating/parsing the request from the CLIENT
    if (!"GET".equalsIgnoreCase(firstLineTokens[0])) {
      throw new InvalidHandshakeException(String
          .format("Invalid request method received: %s Status line: %s", firstLineTokens[0], line));
    }
    if (!"HTTP/1.1".equalsIgnoreCase(firstLineTokens[2])) {
      throw new InvalidHandshakeException(String
          .format("Invalid status line received: %s Status line: %s", firstLineTokens[2], line));
    }
    ClientHandshakeBuilder clienthandshake = new HandshakeImpl1Client();
    clienthandshake.setResourceDescriptor(firstLineTokens[1]);
    return clienthandshake;
  }

  /**
   * Checking the handshake for the role as client
   *
   * @param firstLineTokens the token of the first line split as as an string array
   * @param line            the whole line
   * @return a handshake
   */
  private static HandshakeBuilder translateHandshakeHttpClient(String[] firstLineTokens,
      String line) throws InvalidHandshakeException {
    // translating/parsing the response from the SERVER
    if (!"101".equals(firstLineTokens[1])) {

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