# Can't change Tomcat 9 JDK when running as a Windows service

My Windows 10 already have JAVA_HOME set as environment variable pointing to JDK8. But I want to run this Tomcat 9 with OpenJDK 12.

I download Tomcat 9 64-bit zip. When I run it manually via startup.bat, all I need to do is create bin\setenv.bat and put the new value of JAVA_HOME there as stated in the RUNNING.txt that accompanies the package.

But, if I install Tomcat as a service using service.bat install MyService it uses the JAVA_HOME of Windows, which is expected.

The problem is when I try to follow these instructions to update my installed service and change the Java home.

I tried this with no success:

>tomcat9.exe //US//MyService --JavaHome=path\to\openjdk


I'm doing something wrong?

service.bat install MyService --rename

After, I execute MyServicew.exe and change the JVM in the java tab.