Checking Package Export Versions and Package Import Version Ranges

Author: Eike Stepper

A Java plug-in exports the Java packages it makes available for reuse by other plug-ins. Also, rather than specifying dependencies on other plug-ins Java plug-ins can import other Java packages. Like plug-ins themselves, those exports can specify a version and like plug-in dependencies, Java package imports can specify a version range. Exported Java packages do not automatically inherit the version of their containing plug-in so it's good practice to specify a version for each exported Java package. And just as it's good practice for plug-in dependencies to specify a full dependency range with an inclusive lower bound and an exclusive upper bound, so too it's good practice to specify that for Java package imports. The version manager checks whether each package export specifies a version and whether each package import specifies a proper full version range. It produces an error for each violation.