Japi is a hobby project of mine that is intended to help browsing Java APIs. Everyone knows that looking for a class in for example Java’s standard library isn’t fun at all. IDE’s can help a bit, but I still think that the browser has major advantages in some cases.
Japi works like this. You don’t need an account to search APIs that are already in Japi. However, if you have your own an API, or you know of an API that does not exist in Japi, you can add it yourself. But then you must first sign up.
If you didn’t sign up for Japi, you just check the APIs you want to search in the right sidebar and enter the query. If you did sign up you have a little bit more customization options. To search APIs you must first add it as Watched. You do that by clicking Watch to the right of an API in the list of APIs. Or by visiting a specific API and click Watch. The API will then appear in the right sidebar. To search an API, you simply check it and enter the query.
More information about how to use Japi is found at the Get Started page.