I've been trying many different things throughout various posts, but none of the solutions have helped me.

1. Creating an artifact through Build -> Build artifacts..., selecting directory for META-INF/MANIFEST.MF as main\resources and running a generated jar file throws no main manifest attribute.

2. <..>, selecting directory for META-INF/MANIFEST.MF as main\java and running a generated jar file returns Could not find or load main class.

My MANIFEST.MF:

Manifest-Version: 1.0
Main-Class: <package>.MainApplication

Also, in my build.gradle I have:

jar {
    manifest {
        attributes 'Main-Class': '<package>.MainApplication'
    }
}

I have tried creating a new project, but the problem persisted the same. I hope someone could help me. Thank you.

UPDATE:

Demo project example (FileMail), which produces my error.

Demo project example (MediaFire)

UPDATE 2:

Demo project 2 example