Calling a main class multiple times from a custom gradle task in java

Currently I call a main method in a class like this from my build.gradle file:

task(runSample, dependsOn: 'classes', type: JavaExec) {
      main = 'com.MyMain'
      args 'firstArg'
      args 'secondArg'

I need to do the above but for multiple values of the second args in my custom task implemented in java. I have found an example in groovy that looks like this:

project.javaexec {
    main = ''
    classpath = sourceSets.main.runtimeClasspath
    args 'mrhaki'
    systemProperty 'simple.message', 'Hello '

But in java the project.javaexec takes a closure:

project.javaexec(Closure closure)

Any ideas on how to call the project.javaexec from a task written in Java?

or is this a “groovy-only” feature?