Eclipse collections http://vaskir.blogspot.jp/2016/05/hash-maps-rust-vs-f.html

Main.java

import java.util.Random;

import org.eclipse.collections.api.map.primitive.MutableIntIntMap;
import org.eclipse.collections.impl.factory.primitive.IntIntMaps;


public class Main {

	public static void time(String name, Runnable f) { 
		long s = System.nanoTime();
		f.run();
		System.out.println(String.format("%s: %d elapsed.", name, (long)(((System.nanoTime() - s) / 1e6))));
	}

	public static void main(String[] args) {
		int[] source = new int[50000000];
		Random r = new Random();
		for (int i =0; i < source.length; i++)
			source[i] = r.nextInt();
//		Map<Integer, Integer> m = new HashMap<>();
//		MutableMap<Integer, Integer> m = Maps.mutable.empty();
		MutableIntIntMap m = IntIntMaps.mutable.empty();
		time("Insertion", () -> {
			for (int x : source) {
				m.put(x, 0);
			}
		});
		time("Lookups", () -> {
			int acc = 0;
			for (int x : source) {
				acc += m.get(x) % 10;
			}
			System.out.println(acc);
		});
	}

}
// Insertion: 3399 elapsed.
// Lookups: 1494 elapsed.