When an external tool fails, the jpackage error message is not helpful because the output from the failed tool is suppressed unless jpackage is executed with the "--verbose" flag.

Without the tool's output, the user has no clue about what could be the culprit and assumes this is jpackage's issue. However, the problem could be the tool's misconfiguration.

E.g.: https://github.com/adoptium/adoptium-support/issues/1288

If jpackage fails, it should print the output of the failed external command. The error output should be helpful enough to let the user resolve the configuration problem on the spot.