JavaDoc is what we call the documentation that tells you how to use a java class. You'll learn what a java class is in lesson2.
You can always find these yourself by searching for java 7 and the name of the class, for example:
java 7 String
and then clicking the link to the link that looks something like:
String (Java Platform SE 7 ) - Oracle Documentation
We created some classes that you will use to draw pictures in this course. There is a general description of how the graphics code can be used
There is also JavaDoc for the graphics code. Go Udacity!