Stream test

result.txt

Benchmark                        (size)  Mode  Cnt      Score      Error  Units
StreamTest.wrapWithBrackets          10  avgt   30    151,229 �   15,301  ns/op
StreamTest.wrapWithBrackets         100  avgt   30   1041,827 �   29,505  ns/op
StreamTest.wrapWithBrackets        1000  avgt   30  11097,845 �  289,198  ns/op
StreamTest.wrapWithBracketsLoop      10  avgt   30    112,147 �    6,344  ns/op
StreamTest.wrapWithBracketsLoop     100  avgt   30   1329,546 �   55,875  ns/op
StreamTest.wrapWithBracketsLoop    1000  avgt   30  14293,504 � 2261,672  ns/op

Process finished with exit code 0

StreamTest.java

package org.example;

import org.openjdk.jmh.annotations.*;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.RunnerException;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.stream.IntStream;

@Warmup(iterations = 5, time = 500, timeUnit = TimeUnit.MILLISECONDS)
@Measurement(iterations = 10, time = 500, timeUnit = TimeUnit.MILLISECONDS)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@BenchmarkMode(Mode.AverageTime)
@Fork(3)
@State(Scope.Benchmark)
public class StreamTest {
  @Param({"10", "100", "1000"})
  private int size;
  
  List<String> data;
  
  @Setup
  public void setup() {
    data = IntStream.range(0, size).mapToObj(i -> "hello" + i).toList();
  }
  
  @Benchmark
  public List<String> wrapWithBrackets() {
    return data.stream().map(x -> "[" + x + "]").toList();
  }

  @Benchmark
  public List<String> wrapWithBracketsLoop() {
    List<String> list = new ArrayList<>();
    for (String x : data) {
      list.add("[" + x + "]");
    }
    return list;
  }

  public static void main(String[] args) throws RunnerException {
    Options opt = new OptionsBuilder()
            .include(StreamTest.class.getSimpleName())
            .build();

    new Runner(opt).run();
  }
}