Java in a Nutshell, 5th Edition

Name

Package

Synopsis

This class represents a Java package. You can obtain the Package object for a given Class by calling the getPackage( ) method of the Class object. The static Package.getPackage( ) method returns a Package object for the named package, if any such package has been loaded by the current class loader. Similarly, the static Package.getPackages( ) returns all Package objects that have been loaded by the current class loader. Note that a Package object is not defined unless at least one class has been loaded from that package. Although you can obtain the Package of a given Class, you cannot obtain an array of Class objects contained in a specified Package.

If the classes that comprise a package are contained in a JAR file that has the appropriate attributes set in its manifest file, the Package object allows you to query the title, vendor, and version of both the package specification and the package implementation; all six values are strings. The specification version string has a special format. It consists of one or more integers, separated from each other by periods. Each integer can have leading zeros, but is not considered an octal digit. Increasing numbers indicate later versions. The isCompatibleWith( ) method calls getSpecificationVersion( ) to obtain the specification version and compares it with the version string supplied as an argument. If the package-specification version is the same as or greater than the specified string, isCompatibleWith( ) returns ...