Run only one task from build.gradle [duplicate] - intellij-idea

Question

I have simple build.gradle (or any build.gradle with task that has println)
println GradleVersion.current().prettyPrint()
task task1{
println 'task1 starting'
}
Now when I run $ gradle build I always see tasks executing or print output
task1 starting
:compileJava UP-TO-DATE
:processResources UP-TO-DATE
:classes UP-TO-DATE
:jar
:assemble
:compileTestJava UP-TO-DATE
:processTestResources UP-TO-DATE
:testClasses UP-TO-DATE
:test UP-TO-DATE
:check UP-TO-DATE
:build
BUILD SUCCESSFUL
Total time: 1.291 secs
Why there is always output from println inside tasks?

Answer 1

If You have the following piece of code:
task task1 {
println 'task1 starting'
}
You're in configuration phase of a task. This phase is run during script evaluation. If You'd like to print something while task is executed You need to add an action for task.
It looks like:
task task1 << {
println 'task1 action'
}
This piece of code will be evaluated while the task is being run. << is exactly the same as invoking doLast method on Task's object. You can add many actions.
EDIT
I also highly encourage you to read this blog post.

Answer 2

from Chapter 55. The Build Lifecycle http://www.gradle.org/docs/current/userguide/build_lifecycle.html
// in `settings.gradle`
// println 'This is executed during the initialization phase.'
println 'This is executed during the configuration phase.'
task configure {
println 'This is also executed during the configuration phase.'
}
task execute << {
println 'This is executed during the execution phase.'
}
run with gradle help
output:
This is executed during the initialization phase.
This is executed during the configuration phase.
This is also executed during the configuration phase.
:help
Welcome to Gradle 1.10.
To run a build, run gradle <task> ...
To see a list of available tasks, run gradle tasks
To see a list of command-line options, run gradle --help
BUILD SUCCESSFUL
Total time: 1.882 secs