More Information
For more information about these Java concepts, here are some links to helpful articles available from Wikipedia and Oracle.
Setting the class path:
https://docs.oracle.com/javase/8/docs/technotes/tools/windows/classpath.html
How classes are found:
https://docs.oracle.com/javase/8/docs/technotes/tools/findingclasses.html
JDK Tools and Utilities:
https://docs.oracle.com/javase/8/docs/technotes/tools/