Unable to run / quick star guide ?

[goRaspy]

I tried to use the simulator.
But I can't manage gradle to compile and run the project.

Could you precise if the gradlew script is working ?

When I launch ./gradlew run

Everything is OK before the run

_./gradlew run
:smart-simulator-common:compileJava UP-TO-DATE
:smart-simulator-common:processResources UP-TO-DATE
:smart-simulator-common:classes UP-TO-DATE
:smart-simulator-common:jar UP-TO-DATE
:smart-simulator-core:compileJava UP-TO-DATE
:smart-simulator-core:processResources UP-TO-DATE
:smart-simulator-core:classes UP-TO-DATE
:smart-simulator-core:jar UP-TO-DATE
:smart-simulator-db:compileJava UP-TO-DATE
:smart-simulator-db:processResources UP-TO-DATE
:smart-simulator-db:classes UP-TO-DATE
:smart-simulator-db:jar UP-TO-DATE
:smart-simulator-server:compileJava UP-TO-DATE
:smart-simulator-server:processResources UP-TO-DATE
:smart-simulator-server:classes UP-TO-DATE
:smart-simulator-server:findMainClass
:smart-simulator-server:run FAILED

FAILURE: Build failed with an exception.

• What went wrong:
  Execution failed for task ':smart-simulator-server:run'.

No main class specified_

I suspect a problem with my version of gradle (3.2.1) but I am unable to install 2.3

Many thanks for any help