What is "javadoc"
Javadoc is a documentation generator created by Sun Microsystems to document the API of Java programs from source code. The result is expressed in HTML. It consists basically of some very simple tags inserted in the program comments.
This system is the standard for Java class documentation, and many of the Ides in this language will automatically generate an HTML Javadoc.
It also provides an API for creating doclets and taglets, which allow analysis of the structure of a Java application. That’s how, for example, Jdiff can generate change reports made between two versions of an API.