ToListBench.java

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Level;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;

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

@BenchmarkMode(Mode.AverageTime)
@Fork(value = 1)
@Warmup(iterations = 5, time = 1)
@Measurement(iterations = 10, time = 1)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Benchmark)
public class ToListBench {

    @Param({"10", "1000", "1000000"})
    public int len;

    private Object[] array;

    @Setup(Level.Trial)
    public void setup() {
        array = new Object[len];
        for (int i = 0; i < len; i++) {
            array[i] = Boolean.TRUE;
        }
    }

    @Benchmark
    public List<Object> toList1() {
        return Collections.unmodifiableList(new ArrayList<>(Arrays.asList(array)));
    }

    @Benchmark
    public List<Object> toList2() {
        return Arrays.asList(Arrays.copyOf(array, array.length, Object[].class));
    }
}