/usr/lib/jvm/java-21-openjdk-openj9/bin/jdmpview

The command --help was not recognised
Usage: "jdmpview -core <core_file> [-verbose]" or
       "jdmpview -zip <zip_file> [-verbose]" or
       "jdmpview -version"

To analyze dumps from DDR-enabled JVMs, jdmpview only requires a core file.

The default ImageFactory is null. To change the ImageFactory use:
	 -J-Dcom.ibm.dtfj.image.factoryclass=<classname>

jdmpview can also be used in 'batch mode' whereby commands can be issued without entering an interactive prompt.
This processing is controlled via the following command line options :
        -cmdfile <path to command file> : will read and sequentially execute
                                          a series of jdmpview commands in the specified file
        -charset <character set name>   : specifies the character set for the commands in -cmdfile.
        -outfile <path to output file>  : file to store any output generated by commands
        -overwrite                      : specifies that the file specified by -outfile should be overwritten
        -append                         : specifies that the file specified by -outfile should be appended.

It is possible to execute a single command without specifying a command file by appending the command to the end
 of the command line which executes jdmpview
e.g. jdmpview -core mycore.dmp info class

Finally, some commands which take the * parameter will need to have that specified on the command line as ALL
This is to ensure correct processing by the OS e.g. jdmpview -core mycore.dmp info thread ALL