How to print each element of Multi-line String Parameter?

The code works fine when disabling a Use Groovy Sandbox option and adding @NonCPS helper method. Alternatively, as suggested by @agg3l, proceed to Jenkins management to permit this method access.

So the working code is (same as the 2nd example):

@NonCPS
def printParams() {
    Params.split("\\r?\\n").each { param ->
        println "Param: ${param}"
    }
}
printParams()