Can't run Pinger example

I cloned the jvm-libp2p and attempt to run the Pinger example by

  1. Compile by gradle clean build
  2. Run example by gradle run

with build.gradle.kts having following content added

plugins {
application {
    mainClassName = ""

The result shows that

$ gradle run

> Task :run FAILED
Error: Could not find or load main class
Caused by: java.lang.ClassNotFoundException:

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':run'.
> Process 'command '/home/jason/jdk-11.0.6+10/bin/java'' finished with non-zero exit value 1

Note that the source code is coded with package io.libp2p.example. But neither using nor io.libp2p.example.Pinger in build.gradle.ktsapplication section would work (regardless whether the package name in is package or package io.libp2p.example.

Any suggestion? Thanks