HTTP/2 : Java Glossary

HTTP/2 is a replacement protocol for HTTP (Hypertext Transfer Protocol) (not HTML (Hypertext Markup Language)) to more efficiently download web pages with many resources. It uses many of the ideas pioneered by SPDY (Speedy). It is backwards compatible with HTTP. HTTP/2 servers will work with HTTP browsers, and HTTP/2 browsers will work with HTTP servers. To use it, both server and browser must be modified. In theory, it does not require SSL (Secure Sockets Layer), but in practice, like SPDY, it does. This is odd since SSL defeats caching.

Images can be inlined as gibberish in CSS (Cascading Style Sheets) or HTML documents for more efficient transmission.