HTTP was created by Tim Berners-Lee at CERN in 1989. HTTP/0.9 was first documented in 1991, supporting only GET method. HTTP/1.0 was finalized in 1996, followed by HTTP/1.1 in 1997. HTTP/2 was published in 2015, supporting multiple concurrent requests. HTTP/3 was released in 2022, using QUIC over UDP
Port numbers uniquely identify connection endpoints and direct data to services. Port numbers are 16-bit unsigned integers for TCP and UDP. Port numbers are always associated with network addresses and protocols
HTTP is an application-layer protocol for transmitting hypermedia documents. Follows client-server model with connection establishment and response waiting. Stateless protocol, cookies add state to some client-server interactions
Connection timeout is the time period for establishing a client-server connection. Client stops waiting after timeout if no response is received. HTTP clients allow specifying open and read timeout values
ResponseEntity represents complete HTTP response including status, headers, and body. ResponseEntity is a generic type that can use any response body type. Spring automatically handles response configuration when returned from endpoints
SOAP is a W3C-recommended application communication protocol based on XML. SOAP enables communication between applications across different platforms and technologies. SOAP messages consist of Envelope, Header, Body, and Fault elements