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Array vs List Performance in Java #14078

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May 20, 2023
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Array vs List Performance in Java #14078

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39 changes: 14 additions & 25 deletions ...ns-5/src/main/java/com/baeldung/arrayandlistperformance/ArrayAndArrayListPerformance.java
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,8 @@
import org.openjdk.jmh.runner.options.OptionsBuilder;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.concurrent.TimeUnit;

@State(Scope.Benchmark)
Expand All @@ -16,44 +18,37 @@ public static void main(String[] args) throws Exception {
org.openjdk.jmh.runner.Runner runner = new org.openjdk.jmh.runner.Runner(new OptionsBuilder().include(ArrayAndArrayListPerformance.class.getSimpleName()).forks(1).build());
runner.run();
}

public static Integer[] array = Collections.nCopies(1000000, 1).toArray(new Integer[0]);
public static ArrayList<Integer> list = new ArrayList<Integer>(
Arrays.asList(array));
@Benchmark
public void arrayCreation(Blackhole blackhole) {
int[] array = new int[1000000];
blackhole.consume(array);
public Integer[] arrayCreation() {
return new Integer[1000000];
}

@Benchmark
public void arrayListCreation(Blackhole blackhole) {
ArrayList<Integer> list = new ArrayList<>(1000000);
blackhole.consume(list);
public ArrayList<Integer> arrayListCreation() {
return new ArrayList<>(1000000);
}

@Benchmark
public void arrayItemsSetting(Blackhole blackhole) {
int[] array = new int[1000000];
public Integer[] arrayItemsSetting() {
for (int i = 0; i < 1000000; i++) {
array[i] = i;
}
blackhole.consume(array);

return array;
}

@Benchmark
public void arrayListItemsSetting(Blackhole blackhole) {
ArrayList<Integer> list = new ArrayList<>(1000000);
public ArrayList<Integer> arrayListItemsSetting() {
for (int i = 0; i < 1000000; i++) {
list.add(i);
}
blackhole.consume(list);
return list;
}

@Benchmark
public void arrayItemsRetrieval(Blackhole blackhole) {
int[] array = new int[1000000];
for (int i = 0; i < 1000000; i++) {
array[i] = i;
}
for (int i = 0; i < 1000000; i++) {
int item = array[i];
blackhole.consume(item);
Expand All @@ -62,10 +57,6 @@ public void arrayItemsRetrieval(Blackhole blackhole) {

@Benchmark
public void arrayListItemsRetrieval(Blackhole blackhole) {
ArrayList<Integer> list = new ArrayList<>();
for (int i = 0; i < 1000000; i++) {
list.add(i);
}
for (int i = 0; i < 1000000; i++) {
int item = list.get(i);
blackhole.consume(item);
Expand All @@ -74,14 +65,12 @@ public void arrayListItemsRetrieval(Blackhole blackhole) {

@Benchmark
public void arrayCloning(Blackhole blackhole) {
int[] array = new int[1000000];
int[] newArray = array.clone();
Integer[] newArray = array.clone();
blackhole.consume(newArray);
}

@Benchmark
public void arrayListCloning(Blackhole blackhole) {
ArrayList<Integer> list = new ArrayList<>(1000000);
ArrayList<Integer> newList = new ArrayList<>(list);
blackhole.consume(newList);
}
Expand Down