A JMH microbenchmark comparing sorting performance on Ints.asList vs an actual List.

results.txt

Benchmark                                 Mode  Samples   Score   Error  Units
SortBenchmark.testSortObjectView          avgt        7  10.601 ± 4.034   s/op
SortBenchmark.testSortObjects             avgt        7  13.497 ± 5.649   s/op

SortBenchmark.java

package benchmark;

import java.util.Collections;
import java.util.List;
import java.util.Random;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;
import com.google.common.collect.Lists;
import com.google.common.primitives.Ints;

@State(Scope.Thread)
public class SortBenchmark {

	private final int[] primitives = new int[10_000_000];

	@Setup
	public void fill() {
		Random rand = new Random();
		for (int i = 0; i < primitives.length; ++i) {
			primitives[i] = rand.nextInt();
		}
	}

	@Benchmark
	public int[] testSortObjects() {
		List<Integer> values = Lists.newArrayListWithCapacity(primitives.length);
		for (int i = 0; i < primitives.length; ++i) {
			values.add(primitives[i]);
		}
		Collections.sort(values);
		return Ints.toArray(values);
	}

	@Benchmark
	public int[] testSortObjectView() {
		List<Integer> values = Ints.asList(primitives.clone());
		Collections.sort(values);
		return Ints.toArray(values);
	}

	public static void main(String... args) throws Exception {
		Options opts = new OptionsBuilder()
			.include(SortBenchmark.class.getSimpleName())
			.mode(Mode.AverageTime)
			.warmupIterations(3)
			.measurementIterations(7)
			.jvmArgs("-server")
			.forks(1)
			.build();
		new Runner(opts).run();
	}
}