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extcheck - Unix, Linux Command
extcheck - jar conflict detection utility
-J option ]
extcheck utility checks a specified
jar file for title and
version conflicts with any extensions installed in the JDK
Before installing an extension, you can use this utility
to see if the same or a more recent version of the extension is
extcheck utility compares the Specification-title and
Specification-version headers in the manifest of
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
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.
The following options are supported:
jar files in the extension directory as they are
Additionally, manifest attributes of the target
jar file and any conflicting
jar files are also reported.
-J option ||
option to the Java virtual machine, where
option is one of the options described on the man page for the
java application launcher, java(1). For example,
-J-Xms48m sets the startup memory to 48 megabytes.