Test program to show the performance characteristics of HashMap in Java.

JavaMapTest

package com.serendio.test;

import gnu.trove.map.hash.THashMap;
import gnu.trove.map.hash.TIntIntHashMap;

import java.util.HashMap;
import java.util.Map;

public class JavaMapTest {

	private static final int LOOPSIZE = 1000000;

	public static void main(String args[]) {

		String ints[] = new String[LOOPSIZE];

		for (int i = 0; i < LOOPSIZE; i++) {
			ints[i] = Integer.toString(i);
		}

		long start = System.currentTimeMillis();
		Map<String, Integer> map1 = new HashMap<String, Integer>();
		for (int i = 0; i < LOOPSIZE; i++) {
			map1.put(ints[i], new Integer(i));
		}
		long end = System.currentTimeMillis();
		System.out.println("String hasing Put time:"
				+ Long.toString(end - start));

		start = System.currentTimeMillis();
		for (int i = 0; i < LOOPSIZE; i++) {
			String s = Integer.toString(i);
			map1.get(s);
		}
		end = System.currentTimeMillis();
		System.out.println("String hasing Get time:"
				+ Long.toString(end - start));

		start = System.currentTimeMillis();
		Map<Integer, Integer> map2 = new HashMap<Integer, Integer>();
		for (int i = 0; i < LOOPSIZE; i++) {
			Integer entry = new Integer(i);
			map2.put(entry, entry);
		}
		end = System.currentTimeMillis();
		System.out.println("Integer hashing Put time:"
				+ Long.toString(end - start));

		start = System.currentTimeMillis();
		for (int i = 0; i < LOOPSIZE; i++) {
			Integer entry = new Integer(i);
			map2.get(entry);
		}
		end = System.currentTimeMillis();
		System.out.println("Integer hashing Get time:"
				+ Long.toString(end - start));

		start = System.currentTimeMillis();
		THashMap<Integer, Integer> map3 = new THashMap<Integer, Integer>();
		for (int i = 0; i < LOOPSIZE; i++) {
			Integer entry = new Integer(i);
			map3.put(entry, entry);
		}
		end = System.currentTimeMillis();
		System.out.println("THashMap Integer hashing Put time:"
				+ Long.toString(end - start));

		start = System.currentTimeMillis();
		for (int i = 0; i < LOOPSIZE; i++) {
			Integer entry = new Integer(i);
			map3.get(entry);
		}
		end = System.currentTimeMillis();
		System.out.println("THashMap Integer hashing Get time:"
				+ Long.toString(end - start));

		start = System.currentTimeMillis();
		TIntIntHashMap m4 = new TIntIntHashMap();
		for (int i = 0; i < LOOPSIZE; i++) {
			Integer entry = new Integer(i);
			m4.put(entry, entry);
		}
		end = System.currentTimeMillis();
		System.out.println("TIntIntHashMap Integer hashing Put time:"
				+ Long.toString(end - start));

		start = System.currentTimeMillis();
		for (int i = 0; i < LOOPSIZE; i++) {
			Integer entry = new Integer(i);
			m4.get(entry);
			m4.a
		}
		end = System.currentTimeMillis();
		System.out.println("TIntIntHashMap Integer hashing Get time:"
				+ Long.toString(end - start));

	}

}