Since it’s beginning, Javadoc output has been largely static HTML with navigation links and simple stylesheet styling of its appearance. Java SE 7 saw the first significant change in Javadoc output default appearance in a long time and now it looks like JDK 8 will introduce a new twist on generated Javadoc output. In this post, I look briefly at the more dynamic filtering of methods in Javadoc output by type of method that appears to be available with JDK 8’s javadoc tool.
The following two screen snapshots compare the JDK 7 and JDK 8 versions of default Javadoc output for the Calendar class (chosen for its variety of method types).
Although the Javadoc output for JDK 8 has the same overall styles (including orange “tabs” for “Constructors”, “Fields”, “Methods” and so forth) as Java 7 Javadoc documentation, the methods in the JDK 8 generated documentation have multiple orange tabs above the listing of methods that allow the reader to click on the appropriate tab to see the appropriate subset of methods. The names of the tabs are about as self-explanatory as you could want with names like “All Methods” (all methods on the class), “Static Methods” (class-level methods), “Instance Methods” (object-level methods), “Abstract Methods” (methods without implementation), and “Concrete Methods” (implemented methods).
The next series of screen snapshots demonstrate how clicking on any of these tabs invokes embedded JavaScript code that calls appropriate functions in the script.js file that exists at the root level of the generated Javadoc directory structure.
This is a minor, but still somewhat handy, feature of Javadoc in JDK 8. I have often looked through methods of Javadoc for a class with mixed method types for methods that fit one particular type. Now, rather than needing to scan for keywords such as “static” or “abstract” or for the absence of those same words, I can simply use these “tabs” to filter the types of methods I want to see for a given class.
