I am trying to extend the build task with the name buildAndPost, which after the build completes,
copies the file to the required destination and connects to the server triggering a reload mechanism that automatically reloads the installed plugins (it is also a plugin).
So far I am done with all the code, but one thing is stopping me.
That is, I am accessing the jar file with the following groovy code in build.gradle:

task buildAndPost{
    dependsOn build
    
    doLast{
        File builtFile = tasks.jar.archiveFile.get(); // <----- Here is the problem -----
        PostBuildAction action = new PostBuildAction(builtFile, $serverDir);
    }
}

for my part of code to work that I purely wrote in java at very below of my build script,
it requires the file that is built after performing the build task in the form of Java File object, i.e. java.io.File.

but the line tasks.jar.archiveFile.get() returns an object of something from groovy or gradle api that I currently don’t know.
Using groovy is not my forte (at least the part added more to this java’s superset), and I barely understand it.

How can I get that file as a Java’s File or java.io.File object?