The Doclet API (also called the Javadoc API) provides a mechanism for clients to inspect the source-level structure of programs and libraries, including javadoc comments embedded in the source.

Wikipedia

Activity diagrams are a loosely defined diagram technique for showing workflows of stepwise activities and actions, with support for choice, iteration and concurrency.

A flowchart is a common type of chart, that represents an algorithm or process, showing the steps as boxes of various kinds, and their order by connecting these with arrows.

These diagrams are also called structograms, as they show a program's structures.