gradle: Task :jar SKIPPED while I get my jar with gradlew build - spring-boot

Question

My Question is: Why does the jar-creation work with gradlew build, while I see "Task :jar SKIPPED" when I click on jar in intellij's gradle window ? And how can I fix it in IntelliJ ?
Just created something with spring initializer and loaded the project in intellij as it is.
( it is org.springframework.boot, .. 'org.springframework.boot:spring-boot-starter-web')
I wonder about Task :jar SKIPPED ( nor jar created )
and than I discovered that I get the jar when I start from console.
( and the jar runs fine, it finds the main class - even without jar manifest attribute in build.gradle)
( yesterday I failed in maven with "no main manifest attribute in .... .jar )

Answer 1

This is because Springboot Gradle plugin will create a bootJar task and by default will disable jar and war tasks, as described here: https://docs.spring.io/spring-boot/docs/current/gradle-plugin/reference/html/#packaging-executable-and-normal
So you need to execute bootJar task , from the IDE. When executing gradlew build, the tasks bootJar gets automatically executed, due to tasks dependencies created by the plugin.
When running task build (from console or IDE), you can see the tasks executed by Gradle depending on tasks dependencies, e.g.:
> Task :backend:compileJava
> Task :backend:processResources
> Task :backend:classes
> Task :backend:bootJar ## <== this is the task register by Springboot plugin, which produces the "Fat/executable" jar
> Task :backend:jar SKIPPED ## <== task disabled by Springboot plugin
> Task :backend:assemble
> Task :backend:processTestResources
> Task :backend:testClasses
> Task :backend:test
> Task :backend:check
> Task :backend:build
For your remark
the jar runs fine, it finds the main class - even without jar manifest
attribute in build.gradle
The Springboot plugin will automatically configure this for you, see : https://docs.spring.io/spring-boot/docs/current/gradle-plugin/reference/html/#packaging-executable-configuring-main-class
EDIT 27-05-2021
Starting from Springboot 2.5, the jaris not disabled by default anymore. see more details in release notes here

Answer 2

You can enble this, with add code below in projectName.gradle
it works for me :
spring-boot : 2.0.8.RELEASE
Gradle : 4.5 or >
jar {
baseName = 'projectName'
enabled=true
manifest {
....
}
}