Chapter 5: Hiding the implementation

This chapter covers the way that code is packaged together, and why some parts of
a library are exposed while other parts are hidden. It begins by looking at the
package and import keywords, which perform file-level packaging and allow you
to build libraries of classes. The subject of directory paths and file names is also
examined. The remainder of the chapter looks at the public, private, and protected
keywords, the concept of “friendly” access, and what the different levels of access
control mean when used in various contexts.