Java Servlet Programming

Appendix C. HTTP Status Codes

HTTP status codes are grouped as shown in Table 3.1.

Table C-1. HTTP Status Code Groupings

Code Range	Response Meaning
100-199	Informational
200-299	Client request successful
300-399	Client request redirected, further action necessary
400-499	Client request incomplete
500-599	Server error

Table 3.2 lists the HTTP status code constants defined by the HttpServletResponse interface and used as parameters to its setStatus() and sendError() methods. The version number in the last column refers to the HTTP protocol version that first defined the status code. The Servlet API 2.0 added constants for HTTP Version 1.1 status codes. Note that HTTP 1.1 status codes require an HTTP 1.1-compliant browser.

For more information on HTTP, see Web Client Programming by Clinton Wong (O’Reilly). The proposed HTTP/1.1 specification is available in RFC 2068 at http://www.ietf.org/rfc/rfc2068.txt.

Table C-2. HTTP Status Code Constants

Constant	Code	Default Message	Meaning	HTTP Version
SC_CONTINUE	100	Continue	The server has received the initial part of the request, and the client can continue with the remainder of its request.	1.1
SC_SWITCHING_PROTOCOLS	101	Switching Protocols	The server is willing to comply with the client’s request to switch protocols to the one specified in the request’s Upgrade header. This might include switching to a newer HTTP version.	1.1
SC_OK	200	OK	The client’s request was successful and the server’s response ...