public final class WebSocketCloseStatus
extends Object
implements Comparable<WebSocketCloseStatus>

WebSocket status codes specified in RFC-6455.

 RFC-6455 The WebSocket Protocol, December 2011:
 https://tools.ietf.org/html/rfc6455#section-7.4.1

 WebSocket Protocol Registries, April 2019:
 https://www.iana.org/assignments/websocket/websocket.xhtml

 7.4.1.  Defined Status Codes

 Endpoints MAY use the following pre-defined status codes when sending
 a Close frame.

 1000

    1000 indicates a normal closure, meaning that the purpose for
    which the connection was established has been fulfilled.

 1001

    1001 indicates that an endpoint is "going away", such as a server
    going down or a browser having navigated away from a page.

 1002

    1002 indicates that an endpoint is terminating the connection due
    to a protocol error.

 1003

    1003 indicates that an endpoint is terminating the connection
    because it has received a type of data it cannot accept (e.g., an
    endpoint that understands only text data MAY send this if it
    receives a binary message).

 1004

    Reserved. The specific meaning might be defined in the future.

 1005

    1005 is a reserved value and MUST NOT be set as a status code in a
    Close control frame by an endpoint. It is designated for use in
    applications expecting a status code to indicate that no status
    code was actually present.

 1006

    1006 is a reserved value and MUST NOT be set as a status code in a
    Close control frame by an endpoint. It is designated for use in
    applications expecting a status code to indicate that the
    connection was closed abnormally, e.g., without sending or
    receiving a Close control frame.

 1007

    1007 indicates that an endpoint is terminating the connection
    because it has received data within a message that was not
    consistent with the type of the message (e.g., non-UTF-8 [RFC3629]
    data within a text message).

 1008

    1008 indicates that an endpoint is terminating the connection
    because it has received a message that violates its policy. This
    is a generic status code that can be returned when there is no
    other more suitable status code (e.g., 1003 or 1009) or if there
    is a need to hide specific details about the policy.

 1009

    1009 indicates that an endpoint is terminating the connection
    because it has received a message that is too big for it to
    process.

 1010

    1010 indicates that an endpoint (client) is terminating the
    connection because it has expected the server to negotiate one or
    more extension, but the server didn't return them in the response
    message of the WebSocket handshake. The list of extensions that
    are needed SHOULD appear in the /reason/ part of the Close frame.
    Note that this status code is not used by the server, because it
    can fail the WebSocket handshake instead.

 1011

    1011 indicates that a server is terminating the connection because
    it encountered an unexpected condition that prevented it from
    fulfilling the request.

 1012 (IANA Registry, Non RFC-6455)

    1012 indicates that the service is restarted. a client may reconnect,
    and if it choses to do, should reconnect using a randomized delay
    of 5 - 30 seconds.

 1013 (IANA Registry, Non RFC-6455)

    1013 indicates that the service is experiencing overload. a client
    should only connect to a different IP (when there are multiple for the
    target) or reconnect to the same IP upon user action.

 1014 (IANA Registry, Non RFC-6455)

    The server was acting as a gateway or proxy and received an invalid
    response from the upstream server. This is similar to 502 HTTP Status Code.

 1015

    1015 is a reserved value and MUST NOT be set as a status code in a
    Close control frame by an endpoint. It is designated for use in
    applications expecting a status code to indicate that the
    connection was closed due to a failure to perform a TLS handshake
    (e.g., the server certificate can't be verified).


 7.4.2. Reserved Status Code Ranges

 0-999

    Status codes in the range 0-999 are not used.

 1000-2999

    Status codes in the range 1000-2999 are reserved for definition by
    this protocol, its future revisions, and extensions specified in a
    permanent and readily available public specification.

 3000-3999

    Status codes in the range 3000-3999 are reserved for use by
    libraries, frameworks, and applications. These status codes are
    registered directly with IANA. The interpretation of these codes
    is undefined by this protocol.

 4000-4999

    Status codes in the range 4000-4999 are reserved for private use
    and thus can't be registered. Such codes can be used by prior
    agreements between WebSocket applications. The interpretation of
    these codes is undefined by this protocol.
 

While WebSocketCloseStatus is enum-like structure, its instances should NOT be compared by reference. Instead, either equals(Object) should be used or direct comparison of code() value.