ADDITIONAL SYSTEM INFORMATION :
VirtualBox Windows 10
JDK 16.0.1
11.0.11 for Graal

A DESCRIPTION OF THE PROBLEM :
An additional directory level ends up in a jpackage application for GraalVM.
An install file is successfully created and when run it successfully creates an application.
However, the resulting application has an additional directory inserted in the structure.
 

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Downloading the GraalVM JDK 11 (21.1.0) release resulted in the directories
GraalVM-ce-java11-windows-amd64-21.1.0
...graalvm-ce-java11-21.1.0
......bin
......conf
and remaining jdk files

I moved the graalvm-ce.java11-21.0.0 to the c:\Program Files\Java directory

Either having the GraalVM the default installed JDK for jpackage or using --runtime-image with the graalvm jdk.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
An application in Program Files with a directory
runtime
...bin
...conf
...
ACTUAL -
An application in Program Files with a directory
runtime
...graalvm-ce-java11-21.1.0
......bin
......conf
...

---------- BEGIN SOURCE ----------
Issuing the jpackage command indicating an installed GraalVM jdk with it's original name should reproduce.
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
I renamed the GraalVM to jdk-11 and got a correct directory structure.

FREQUENCY : always