Gradle build failed: Main class name has not been configured and it could not be resolved

If you are building multi-module project, and including a module that is not the springboot project, then you should put this on gradle.build which in the non-springboot module.

bootJar {
    enabled = false
}

jar {
    enabled = true
}

I ran into this error when I used kotlin and misplaced the main method.

Wrong:

@SpringBootApplication
class Application {
    fun main(args: Array<String>) {
        runApplication<Application>(*args)
    }
}

Fix (moved main out of Application):

@SpringBootApplication
class Application

fun main(args: Array<String>) {
    runApplication<Application>(*args)
}

So, you can configure it. Pls try:

apply plugin: 'application'
mainClassName = 'com.example.WebApplication'