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 2 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-versionheaders in the manifest of the
targetfile.jarfile 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-titleand the same or a newer
Specification-versionnumber, a non-zero error code is returned. A non-zero error code is also returned if
targetfile.jardoes not have the
Specification-versionattributes in its manifest.
- Lists Jar files in the extension directory as they are checked. Additionally, manifest attributes of the target jar file and any conflicting jar files are also reported.
- Pass option to the Java virtual machine, where option is one of the options described on the reference page for the java application launcher. For example, -J-Xms48m sets the startup memory to 48 megabytes.