WebSockets vs. Server-Sent events/EventSource

Question

Both WebSockets and Server-Sent Events are capable of pushing data to browsers. To me they seem to be competing technologies. What is the difference between them? When would

Answer 1

Here is a talk about the differences between web sockets and server sent events. Since Java EE 7 a WebSocket API is already part of the specification and it seems that server sent events will be released in the next version of the enterprise edition.