What is the purpose of defining a package in a Java file? [closed]

by

Let’s start with the definition of a “Java package”, as described in the Wikipedia article:

A Java package is a mechanism for
organizing Java classes into
namespaces similar to the modules of
Modula. Java packages can be stored in
compressed files called JAR files,
allowing classes to download faster as
a group rather than one at a time.
Programmers also typically use
packages to organize classes belonging
to the same category or providing
similar functionality.

So based on that, packages in Java are simply a mechanism used to organize classes and prevent class name collisions. You can name them anything you wish, but Sun has published some naming conventions that you should use when naming packages:

Packages

The prefix of a unique package name is
always written in all-lowercase ASCII
letters and should be one of the
top-level domain names, currently com,
edu, gov, mil, net, org, or one of the
English two-letter codes identifying
countries as specified in ISO Standard
3166, 1981.

Subsequent components of the package
name vary according to an
organization’s own internal naming
conventions. Such conventions might
specify that certain directory name
components be division, department,
project, machine, or login names.

Examples:

  • com.sun.eng

  • com.apple.quicktime.v2

  • edu.cmu.cs.bovik.cheese

More Related Contents:

  1. How can I solve “java.lang.NoClassDefFoundError”?
  2. What is the convention for word separator in Java package names?
  3. Java packages com and org
  4. Running java in package from command line
  5. Are there best practices for (Java) package organization? [closed]
  6. What is the default package in which my classes are put if I don’t specify it?
  7. How to include the Spongy Castle JAR in Android?
  8. Why should java package name be lowercase?
  9. How to compile java package structures using javac
  10. Compiling multiple packages using the command line in Java
  11. Do unused import and objects have a performance impact?
  12. What strategy do you use for package naming in Java projects and why? [closed]
  13. Java Package Does Not Exist Error
  14. Prohibited package name: java
  15. Package structure for a Java project?
  16. Java Package Vs Folder-Structure? what is the difference
  17. How to wildcard include JAR files when compiling?
  18. Extract links from a web page
  19. How to get current class name including package name in Java?
  20. How to run a .class file that is part of a package from cmd?
  21. Difference between Package and Directory in Java
  22. Why subclass in another package cannot access a protected method?
  23. URLClassLoader and accessibility of package-private methods
  24. Java error – bad source file: file does not contain class x . Please remove or make sure it appears
  25. Java: Use import or explicit package / class name?
  26. Call protected method from a subclass of another instance of different packages
  27. Why can’t my subclass access a protected variable of its superclass, when it’s in a different package?
  28. Why do java source files require package declarations?
  29. When should I use “this” in a class?
  30. Using static variables in Android

Leave a Comment