Singleton benchmark

/* MAIN CLASS */
package dk.xakeps.benchmarks.instancespeed;

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.concurrent.TimeUnit;

@State(Scope.Thread)
@BenchmarkMode(Mode.Throughput)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public class Main {
    private static Main instance;

    public static Main getInstance() {
        if(instance == null) {
            instance = new Main();
        }
        return instance;
    }

    @Benchmark
    public void constructorTest() {
        new TestClass(this);
    }

    @Benchmark
    public void instanceTest() {
        TestClass.getInstance();
    }

    public static void main(String[] args) throws RunnerException {
        Options options = new OptionsBuilder()
                .include(Main.class.getSimpleName())
                .warmupIterations(10)
                .measurementIterations(5)
                .forks(5)
                .build();
        new Runner(options).run();
    }
}

/* TESTING CLASS */
package dk.xakeps.benchmarks.instancespeed;

public class TestClass {
    private Main mainClass;
    private static final class Holder {
        static final TestClass instance = new TestClass();
    }

    private TestClass() {

    }

    public TestClass(Main main) {
        this.mainClass = main;
    }

    public static TestClass getInstance() {
        return Holder.instance;
    }
}

/* RESULTS */
/*
Result "constructorTest":
  3,743 ±(99.9%) 0,240 ops/ns [Average]
  (min, avg, max) = (3,208, 3,743, 4,157), stdev = 0,321
  CI (99.9%): [3,503, 3,983] (assumes normal distribution)

Result "instanceTest":
  3,762 ±(99.9%) 0,088 ops/ns [Average]
  (min, avg, max) = (3,515, 3,762, 3,919), stdev = 0,117
  CI (99.9%): [3,675, 3,850] (assumes normal distribution)


# Run complete. Total time: 00:02:32

Benchmark              Mode  Cnt  Score   Error   Units
Main.constructorTest  thrpt   25  3,743 ± 0,240  ops/ns
Main.instanceTest     thrpt   25  3,762 ± 0,088  ops/ns

HIGHER - BETTER
*/