Packages

What are packages?

• Packages are help provide modularity.
• Related classes can be grouped together in packages.
• Packages may share data (friendly access mode).
• Interfaces can be used to define standard set of methods for a package.
• Packages are a good way to distribute programming environments.

Why Modularity?

• Complexity of programs tends to grow exponentially with length.
• The effort expended programming tends to grow exponentially with length.
• The useful output of programs grows sublinearly.
• Maintanance of a worthwhile program costs many times the initial production cost.
• Modularity isolates different portions of the task.
• The "interface" (not in the Java sense) between modules should be small.
  • The "interface" is the public variables and public methods.

Hence:
• Modularity tends to make programming task grow more linearly.
• Modualrity makes programs more maintainable.