(a) Put your interface and classes from Exercise 13 (shapes) into a package called net.grelf.course and see how to use the -d compiler option to put the .class files in the right place so they can be imported into other files (eg, make a simple test program which imports them).
You may need to use
javac -d . *.java
to compile all classes at once, because of interdependencies.
(b) Run (in the command window)
javadoc -d docs *.java
and look at the result in a web browser, starting at docs/index.html