Java Performance of Array vs ArrayList: http://stackoverflow.com/q/30217484/3281722

Main.java

package de.fxnn.arraylistvsarray;

import java.util.ArrayList;
import java.util.EnumMap;
import java.util.List;
import java.util.Map;
import java.util.Random;

public class Main {

    protected enum TestCase {
        CREATE_PRIMITIVE_ARRAY,
        CREATE_ARRAY_LIST,
        MAX_OVER_PRIMITIVE_ARRAY,
        MAX_OVER_ARRAY_LIST
    }

    protected static final int LOOP_SIZE = 1000000;

    protected static final Random RANDOM = new Random();

    public static void main(String[] args) {
        Map<TestCase, List<Double>> result = new EnumMap<>(TestCase.class);
        for (TestCase testCase : TestCase.values()) {
            result.put(testCase, new ArrayList<>());
        }

        for (int i = 0; i < 100; i++) {
            System.out.println("Iteration " + i);
            Map<TestCase, Double> iterationResults = runPerformanceTests();
            for (TestCase testCase : iterationResults.keySet()) {
                result.get(testCase).add(iterationResults.get(testCase));
            }
            System.out.println();
        }

        for (TestCase testCase : result.keySet()) {
            double average = 0.0;
            for (Double iterationResult : result.get(testCase)) {
                average += iterationResult;
            }
            average = average / result.get(testCase).size();

            System.out.println("Test case " + testCase + " average time: " + average + " ms");
        }
    }

    private static Map<TestCase, Double> runPerformanceTests() {
        Map<TestCase, Double> result = new EnumMap<>(TestCase.class);

        long millis;
        millis = System.currentTimeMillis();
        ArrayList<Integer> arrayList = createArrayList(LOOP_SIZE);
        millis = System.currentTimeMillis() - millis;
        System.out.println("Creating array list with " + LOOP_SIZE + " elements took " + millis + " ms");
        result.put(TestCase.CREATE_ARRAY_LIST, (double) millis);

        millis = System.currentTimeMillis();
        loopOverArrayList(arrayList);
        millis = System.currentTimeMillis() - millis;
        System.out.println("Loop over array list with " + LOOP_SIZE + " elements took " + millis + " ms");
        result.put(TestCase.MAX_OVER_ARRAY_LIST, (double) millis);

        millis = System.currentTimeMillis();
        int[] array = createArray(LOOP_SIZE);
        millis = System.currentTimeMillis() - millis;
        System.out.println("Creating array with " + LOOP_SIZE + " elements took " + millis + " ms");
        result.put(TestCase.CREATE_PRIMITIVE_ARRAY, (double) millis);

        millis = System.currentTimeMillis();
        loopOverArray(array);
        millis = System.currentTimeMillis() - millis;
        System.out.println("Loop over array with " + LOOP_SIZE + " elements took " + millis + " ms");
        result.put(TestCase.MAX_OVER_PRIMITIVE_ARRAY, (double) millis);

        return result;
    }

    private static int loopOverArray(int[] array) {
        int max = Integer.MIN_VALUE;

        for (int element : array) {
            max = Math.max(element, max);
        }

        return max;
    }

    private static int loopOverArrayList(ArrayList<Integer> arrayList) {
        int max = Integer.MIN_VALUE;

        for (Integer element : arrayList) {
            max = Math.max(element, max);
        }

        return max;
    }

    private static int[] createArray(int loopSize) {
        int[] result = new int[loopSize];

        for (int i = 0; i < loopSize; i++) {
            result[i] = RANDOM.nextInt();
        }

        return result;
    }

    private static ArrayList<Integer> createArrayList(int loopSize) {
        ArrayList<Integer> result = new ArrayList<>(loopSize);

        for (int i = 0; i < loopSize; i++) {
            result.add(RANDOM.nextInt());
        }

        return result;
    }
}