Packages are used in Java in order to prevent naming conflicts,to control access, to make seraching/locating and usageof classes,interfaces,enumberations,annotations easier etc.
some of the existing packages in Java are:Java.lang – bundles the fundamental classes
java.io – classes of imput, output functions are bundled in this package
example:
http://www.tutorialspoint.com/java/java_packages.htm