How to use value of one registry entry into another

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One of my windows service uses the java.exe to run. The path where java lies in my C drive is stored in a registry entry. Java keeps updating its revision when updates happens and it keeps deleting the old folder and creates a new one. This new path needs to be updated in my registry entry other wise my windows service stops.
One solution I can think is use the registry entry that points to java path as a value in my registry entry, so that my reg entry does not have a hard coded java path.

Basically I want to use the value at this registry entry(which is C:\Program Files (x86)\Java\jre1.8.0_131\bin\javaws.exe)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\windows\CurrentVersion\App Paths\javaws.exe

in other registry entry : HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EngineWithJenkins\Parameters@Path

What I have tried:

I have used these two methods but they failed:

$(Registry:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\windows\CurrentVersion\App Paths\javaws.exe@Path)

and directly the path

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\windows\CurrentVersion\App Paths\javaws.exe\Path