ADDITIONAL SYSTEM INFORMATION :
macOS 10.13.6

A DESCRIPTION OF THE PROBLEM :
jpackage started with --mac-sign option fails to sign the .app file because it is already signed with some Oracle certificate 
Codesign utility is called without -f option so it will not replace existing signature and fail.


jpacker output:

MacBook-Pro-User:build user$ ~/Desktop/jdk-14.jdk/Contents/Home/bin/jpackage --input app --main-jar CompanyName.jar --name CompanyName --dest dmg --icon CompanyName.icns --mac-package-identifier CompanyName --mac-package-name CompanyName --mac-sign --temp tmp
WARNING: Using incubator modules: jdk.incubator.jpackage
java.io.IOException: Command [codesign, -s, Developer ID Application: CompanyName Ltd. (***), -vvvv, tmp/images/image-13885023430950711627/CompanyName.app] exited with 1 code


Then I check the signature and see:

MacBook-Pro-User:build user$ codesign -dvvvv tmp/images/image-13885023430950711627/CompanyName.app
Executable=/Users/user/IdeaProjects/CompanyName/build/tmp/images/image-13885023430950711627/CompanyName.app/Contents/MacOS/CompanyName
Identifier=jpackageapplauncher
Format=app bundle with Mach-O thin (x86_64)
CodeDirectory v=20500 size=383 flags=0x10000(runtime) hashes=3+5 location=embedded
VersionPlatform=1
VersionMin=657664
VersionSDK=658944
Hash type=sha256 size=32
CandidateCDHash sha1=aa04c6adeac031e731ada82702d486ebb8fbf48d
CandidateCDHash sha256=c34c5c3c88de5c3ae6167d6494776da87b288c86
Hash choices=sha1,sha256
Page size=4096
CDHash=c34c5c3c88de5c3ae6167d6494776da87b288c86
Signature size=9059
Authority=Developer ID Application: Oracle America, Inc. (VB5E2TV963)
Authority=Developer ID Certification Authority
Authority=Apple Root CA
Timestamp=Feb 6, 2020 at 21:03:52
Info.plist=not bound
TeamIdentifier=VB5E2TV963
Runtime Version=10.14.0


FREQUENCY : always