I found some sample code that uses an interface named com.sun.jersey.spi.container.ContainerRequestFilter. Someone was nice enough to post the javadoc here, but it just looks like it was some university professor who also couldn't find the javadocs. I know I can build it myself, but would rather not go through the work. Is there a central place to get javadocs like these?
I looked here and here the first was closed the second was just a fancy google search.
There's the maven central repo. It has javadocs to go with many, but by no means all, of the libraries it hosts. That isn't something you can just browse to, you can only download the javadoc in jars.
EDIT:
As you might notice all the examples pointed out by you and others sites mentioned in answers don't do theirs job because it's hard to find all new api and track all api changes and present it in reasonable manner (plethora of versions). Even dzone.com child jdocs.com serves javadoc for out of date versions. Jarvana as a Maven focused search engine offers a great solution to find appropriate javadoc if it deployed to Maven repositories. We as developers have to influence library creators to deploy their software to Maven repositories with javadoc generated and support creator of Jarvana :)
JDocs contains lots of libraries. It even used to contain the JDK JavaDoc as well but Sun made them remove it!
This looks like it: https://jersey.dev.java.net/nonav/apidocs/latest/jersey/index.html
Did a google search for 'sun jersey'.