Status Code
Associated Message
Meaning
100
Continue
Continue with partial request. (New in HTTP 1.1)
101
Switching Protocols
Server will comply with Upgrade header and change to different protocol. (New in HTTP 1.1)
200
OK
Everything's fine; document follows for GET and POST requests. This is the default for servlets; if you don't use setStatus, you'll get this.
201
Created
Server created a document; the Location header indicates its URL.
202
Accepted
Request is being acted upon, but processing is not completed.
203
Non-Authoritative Information
Document is being returned normally, but some of the response headers might be incorrect since a document copy is being used. (New in HTTP 1.1)
204
No Content
No new document; browser should continue to display previous document. This is a useful if the user periodically reloads a page and you can determine that the previous page is already up to date. However, this does not work for pages that are automatically reloaded via the Refresh response header or the equivalent <META HTTP-EQUIV="Refresh" ...> header, since returning this status code stops future reloading. JavaScript-based automatic reloading could still work in such a case, though.
205
Reset Content
No new document, but browser should reset document view. Used to force browser to clear CGI form fields. (New in HTTP 1.1)
206
Partial Content
Client sent a partial request with a Range header, and server has fulfilled it. (New in HTTP 1.1)
300
Multiple Choices
Document requested can be found several places; they'll be listed in the returned document. If server has a preferred choice, it should be listed in the Location response header.
301
Moved Permanently
Requested document is elsewhere, and the URL for it is given in the Location response header. Browsers should automatically follow the link to the new URL.
302
Found
Similar to 301, except that the new URL should be interpreted as a temporary replacement, not a permanent one. Note: the message was "Moved Temporarily" in HTTP 1.0, and the constant in HttpServletResponse is SC_MOVED_TEMPORARILY, not SC_FOUND.
Very useful header, since browsers automatically follow the link to the new URL. This status code is so useful that there is a special method for it, sendRedirect. Using response.sendRedirect(url) has a couple of advantages over doing response.setStatus(response.SC_MOVED_TEMPORARILY) and response.setHeader("Location", url). First, it is easier. Second, with sendRedirect, the servlet automatically builds a page containing the link (to show to older browsers that don't automatically follow redirects). Finally, sendRedirect can handle relative URLs, automatically translating them to absolute ones.
Note that this status code is sometimes used interchangeably with 301. For example, if you erroneously ask for
http://host/~user (missing the trailing slash), some servers will send 301 and others will send 302.
Technically, browsers are only supposed to automatically follow the redirection if the original request was GET. See the 307 header for details.
303
See Other
Like 301/302, except that if the original request was POST, the redirected document (given in the Location header) should be retrieved via GET. (New in HTTP 1.1)
304
Not Modified
Client has a cached document and performed a conditional request (usually by supplying an If-Modified-Since header indicating that it only wants documents newer than a specified date). Server wants to tell client that the old, cached document should still be used.
305
Use Proxy
Requested document should be retrieved via proxy listed in Location header. (New in HTTP 1.1)
307
Temporary Redirect
This is identical to 302 ("Found" or "Temporarily Moved"). It was added to HTTP 1.1 since many browsers erroneously followed the redirection on a 302 response even if the original message was a POST, even though it really ought to have followed the redirection of a POST request only on a 303 response. This response is intended to be unambigously clear: follow redirected GET
and POST requests in the case of 303 responses, only follow the redirection for GET requests in the case of 307 responses. Note: for some reason there is no constant in HttpServletResponse corresponding to this status code. (New in HTTP 1.1)
400
Bad Request
Bad syntax in the request.
401
Unauthorized
Client tried to access password-protected page without proper authorization. Response should include a WWW-Authenticate header that the browser would use to pop up a username/password dialog box, which then comes back via the Authorization header.
403
Forbidden
Resource is not available, regardless of authorization. Often the result of bad file or directory permissions on the server.
404
Not Found
No resource could be found at that address. This is the standard "no such page" response.
This is such a common and useful response that there is a special method for it in HttpServletResponse: sendError(message). The advantage of sendError over setStatus is that, with sendError, the server automatically generates an error page showing the error message.
405
Method Not Allowed
The request method (GET, POST, HEAD, DELETE, PUT, TRACE, etc.) was not allowed for this particular resource. (New in HTTP 1.1)
406
Not Acceptable
Resource indicated generates a MIME type incompatible with that specified by the client via its Accept header. (New in HTTP 1.1)
407
Proxy Authentication Required
Similar to 401, but proxy server must return a Proxy-Authenticate header. (New in HTTP 1.1)
408
Request Timeout
The client took too long to send the request. (New in HTTP 1.1)
409
Conflict
Usually associated with PUT requests; used for situations such as trying to upload an incorrect version of a file. (New in HTTP 1.1)
410
Gone
Document is gone; no forwarding address known. Differs from 404 in that the document is is known to be permanently gone in this case, not just unavailable for unknown reasons as with 404. (New in HTTP 1.1)
411
Length Required
Server cannot process request unless client sends a Content-Length header. (New in HTTP 1.1)
412
Precondition Failed
Some precondition specified in the request headers was false. (New in HTTP 1.1)
413
Request Entity Too Large
The requested document is bigger than the server wants to handle now. If the server thinks it can handle it later, it should include a Retry-After header. (New in HTTP 1.1)
414
Request URI Too Long
The URI is too long. (New in HTTP 1.1)
415
Unsupported Media Type
Request is in an unknown format. (New in HTTP 1.1)
416
Requested Range Not Satisfiable
Client included an unsatisfiable Range header in request. (New in HTTP 1.1)
417
Expectation Failed
Value in the Expect request header could not be met. (New in HTTP 1.1)
500
Internal Server Error
Generic "server is confused" message. It is often the result of CGI programs or (heaven forbid!) servlets that crash or return improperly formatted headers.
501
Not Implemented
Server doesn't support functionality to fulfill request. Used, for example, when client issues command like PUT that server doesn't support.
502
Bad Gateway
Used by servers that act as proxies or gateways; indicates that initial server got a bad response from the remote server.
503
Service Unavailable
Server cannot respond due to maintenance or overloading. For example, a servlet might return this header if some thread or database connection pool is currently full. Server can supply a Retry-After header.
504
Gateway Timeout
Used by servers that act as proxies or gateways; indicates that initial server didn't get a response from the remote server in time. (New in HTTP 1.1)
505
HTTP Version Not Supported
Server doesn't support version of HTT
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