SimpleBenchmark.scala

import java.util.ArrayList
import java.util.LinkedList
import java.util.List

trait Benchmark { 
  def run(func: => Unit) = { 
    val startedAt = System.currentTimeMillis
    func
    val stoppedAt = System.currentTimeMillis
    println("Time taken is :" + (stoppedAt - startedAt))
  }
}

object App extends Benchmark { 
  val count = 2000000
  def main(args: Array[String]) = {
    println("What follows involves JVM warmup and hence ignore")
    run { 
      iterateUsingArrayList
    }
    run { 
      iterateUsingLinkedList
    }
    println("Running first iteration is done")
    Thread.sleep(2*400)
    run { 
      iterateUsingArrayList
    }
    run { 
      iterateUsingLinkedList
    }
    println("Running second iteration done")
    Thread.sleep(10*1000)
  }

  def iterateUsingArrayList = { 
    val a: List[String] = new ArrayList()

    for(x <- 0 to count) a.add("hello " + x)

    val iterator = a.iterator()
    while(iterator.hasNext()) { 
      iterator.next()
    }
  }

  def iterateUsingLinkedList = { 
    val a: List[String] = new LinkedList()

    for(x <- 0 to count) a.add("hello " + x)

    val iterator = a.iterator()
    while(iterator.hasNext()) { 
      iterator.next()
    }
  }
}