extcheck detects version conflicts between a target jar file and currently installed extension jar files.
extcheck [ -verbose ] targetfile.jar
The extcheck utility checks a specified Jar file for title and version conflicts with any extensions installed in the Java™ SDK. Before installing an extension, you can use this utility to see if the same or a more recent version of the extension is already installed.
The extcheck utility compares the
Specification-title and
Specification-version headers in the manifest of the
targetfile.jar file against the corresponding headers
in all Jar files currently installed in the extension directory.
(The extension directory is jre/lib/ext by default.) The
extcheck utility compares version numbers in the same way as
the method java.lang.Package.isCompatibleWith.
If no conflict is detected, the return code is 0.
If the manifest of any jar file in the extensions directory has
the same Specification-title and the same or a newer
Specification-version number, a non-zero error code is
returned. A non-zero error code is also returned if
targetfile.jar does not have the
Specification-title or
Specification-version attributes in its manifest.
