spring-boot/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/packaging/boot-jar-and-jar.gradle.kts

import org.springframework.boot.gradle.tasks.bundling.BootJar

plugins {
	java
	id("org.springframework.boot") version "{version}"
}

// tag::enable-jar[]
tasks.getByName<Jar>("jar") {
	enabled = true
}
// end::enable-jar[]

// tag::classifier[]
tasks.getByName<BootJar>("bootJar") {
	classifier = "boot"
}
// end::classifier[]

tasks.getByName<BootJar>("bootJar") {
	mainClassName = "com.example.Application"
}