HTTP status codes 301 and 302 codes are basically used for redirection which means another request need to be made in order to complete the HTTP request as the content is located elsewhere.So the web page which replies with either 301 or 302 HTTP status codes, the really do not return any HTML, but includes Location: HTTP header indicatingnext URL where content is present.

301 status code indicates that a resource has been permanently moved.It also indicates to search engines that link equity from the previous

URL should be credited to the new one. So the new page will inherit the rankings of the original page.

However, 302 status code indicates that resource is temporarily moved.There can be internal temporary redirects, that is, from a page on domain A
to another page on domain A, and external temporary redirects, from a page on domain A to a page on domain B.

Generally most search engines only use it for an internal 302. External 302 redirects are really dangerous. Since in such cases search engine will list the result with the destination result, that is, domain B, instead of domain A. This is against the standard and is knowed by the name 302 hijacking.

302 hijacking refers to the practice of using a page on domain A to link to a page on domain B, which has fresh quality content.