The API used for application development has not yet been finalised. Rather
than document something here that will quickly be out of date, please see the
Javadoc for the
org.apache.catalina.websocket package. The Javadoc
pages are not included with Tomcat binary distributions. To view them
locally you would have to download and install "Full documentation"
distribution, or build it from sources. You can
also read this on the Apache Tomcat web site. Start with the
WebSocketServlet class.
There are also several example applications that demonstrate how the
WebSocket API can be used. You'll need to look at both the client side
html and the server side
code.
Do keep in mind that the API is fluid and is likely to change, possibly
significantly, between point releases. The documentation will be updated once
the API is considered stable (unlikely to be until JSR 356 is complete).
