The target JAR file against which the currently installed extension JAR files are compared to detect version conflicts\&.
.SHDESCRIPTION
The \f3extcheck\fR command checks a specified JAR file for title and version conflicts with any extensions installed in the Java SE SDK\&. Before installing an extension, you can use this utility to see whether the same or a more recent version of the extension is already installed\&.
.PP
The \f3extcheck\fR command compares the Specification-title and Specification-version headers in the manifest of the \f3targetfile\&.jar\fR file against the corresponding headers in all JAR files currently installed in the extension directory\&. By default, the extension directory is \f3jre/lib/ext\fR on Oracle Solaris and \f3\ejre\elib\eext\fR on Windows\&. The \f3extcheck\fR command compares version numbers in the same way as the \f3java\&.lang\&.Package\&.isCompatibleWith\fR method\&.
.PP
If no conflict is detected, then the return code is 0\&.
.PP
If the manifest of any JAR file in the extensions directory has the same \f3Specification-title\fR and the same or a newer \f3Specification-version\fR number, then a non-zero error code is returned\&. A non-zero error code is also returned when \f3targetfile\&.jar\fR does not have the \f3Specification-title\fR or \f3Specification-version\fR attributes in its manifest file\&.
.SHOPTIONS
.TP
-verbose
.br
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\&.
.TP
-J\fIoption\fR
.br
Passes \fIoption\fR to the Java Virtual Machine (JVM), where option is one of the options described on the reference page for the Java launcher\&. For example, \f3-J-Xms48m\fR sets the startup memory to 48 MB\&. See java(1)\&.
