Benchmarks different types of for-cycle in Groovy 2.4.7

ForBenchmarks.groovy

package ib.groovy

import org.openjdk.jmh.annotations.Benchmark
import org.openjdk.jmh.annotations.Fork
import org.openjdk.jmh.annotations.Measurement
import org.openjdk.jmh.annotations.OutputTimeUnit
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 org.openjdk.jmh.infra.Blackhole

import java.util.concurrent.TimeUnit

@Fork(value = 4, warmups = 2)
@Measurement(iterations = 8)
@Warmup(iterations = 4)
@OutputTimeUnit(TimeUnit.MILLISECONDS)
@State(Scope.Benchmark)
class ForBenchmarks {

    private List<Integer> values;

    @Setup
    void setup() {
        values = new ArrayList<>(1 << 17)
        for (int i = 0; i < values.size(); i++) {
            values.add(i);
        }
    }

    @Benchmark
    void testEach(Blackhole bh) {
        values.each { bh.consume(it) }
    }

    @Benchmark
    void testForIn(Blackhole bh) {
        for (i in values) {
            bh.consume(i)
        }
    }

    @Benchmark
    void testForEach(Blackhole bh) {
        for (Integer i : values) {
            bh.consume(i)
        }
    }

    @Benchmark
    void testFor(Blackhole bh) {
        for (int i = 0; i < values.size(); i++) {
            bh.consume(values.get(i))
        }
    }
}

/**

 Benchmark                   Mode  Cnt       Score      Error   Units
 ForBenchmarks.testEach     thrpt   32   10889.306 ±  406.861  ops/ms
 ForBenchmarks.testFor      thrpt   32  105201.557 ± 4435.814  ops/ms
 ForBenchmarks.testForEach  thrpt   32  138256.978 ± 1699.157  ops/ms
 ForBenchmarks.testForIn    thrpt   32  137114.933 ± 2802.429  ops/ms
 
i7-4770, 32Gb RAM
Benchmark                   Mode  Cnt       Score      Error   Units
ForBenchmarks.testEach     thrpt   32   10983.740 ±  536.228  ops/ms
ForBenchmarks.testFor      thrpt   32  121392.489 ± 1944.488  ops/ms
ForBenchmarks.testForEach  thrpt   32  162295.392 ± 3246.866  ops/ms
ForBenchmarks.testForIn    thrpt   32  156622.444 ± 5791.028  ops/ms
 */