Example Three: How to turn an array into an ArrayList in Java using Google Guava.

how-to-convert-an-array-to-an-arraylist-in-java-using-google-guava.groovy

@Grab(group='com.jamonapi', module='jamon', version='2.82')
import com.jamonapi.Monitor
import com.jamonapi.MonitorFactory

@Grab(group='com.google.guava', module='guava', version='32.1.3-jre')
import static com.google.common.collect.Lists.newArrayList

import java.util.stream.Collectors
import java.util.List
import java.util.Arrays
import java.util.Random

def random = new Random()

def arrayCapacity = 10000

def numbers = new java.lang.Integer[arrayCapacity + 1]

for (int ctr in 0..arrayCapacity) {
    numbers[ctr] = Integer.valueOf (random.nextInt())
}

def iterations = 100000

def monitor = MonitorFactory.start("Convert an array to an ArrayList performance monitor via Google Guava example")

for (ctr in 0..iterations) {
  def exampleList = newArrayList (numbers) as java.util.List
}

monitor.stop ()

println "iterations: $iterations, performance: $monitor"

return;

See the following article: How To Convert An Array To An ArrayList In Java!

With the requirement to autobox due to line #17 using a primitive int array (see line #28), the script will take ~166 seconds to run, on average, on my laptop. This number is not accurate however since autoboxing is an expensive operation. Once we've fixed this issue and retested we can see the time drops to ~3.7 seconds.