Should this installation or the execution of the batch files not work for you ... JAR execution via command line (all platforms): Every release has the executable JAR "MORTAR-fat-1.3.0.0.jar" attached ...
The runtime image gcr.io/google-appenine/openjdk:8 will be automatically selected if you are attempting to deploy a JAR (*.jar file). That will add the JAR ... passed command line arguments to look ...