一段代码

package com.maxthon;

import java.util.Collections;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;

public class TestMap {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		//final ConcurrentHashMap<String, String> map = new ConcurrentHashMap<String, String>();
		final Map<String, String> map = Collections.synchronizedMap(new HashMap<String, String>());
		final Hashtable<String, String> table = new Hashtable<String, String>();
		final Runnable run2 = new Runnable() {
			@Override
			public void run() {
				Set<Entry<String, String>> set = table.entrySet();
				
				synchronized (this) {
					int i = 0;
					for (Entry<String, String> en : set) {
						System.out.println(en.getKey() + ": " + en.getValue());
						i++;
					}
					System.out.println("the count is: " + i);
				}

			}
		};

		Runnable run1 = new Runnable() {

			@Override
			public void run() {
				int i = 0;
					while (i < 1000) {
						table.put("key" + i, "" + i);
						i++;
					}
				}
			

		};
		new Thread(run1).start();
		new Thread(run2).start();
	}

}