Timing test of Java's SimpleDateFormat

gistfile1.java

package com.edatasource.receipts.parser;

import org.junit.Test;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**
 * SimpleDateFormat is not thread safe, so you'll need to either lock the thread when
 * you run format.parse() or create a new SimpleDateFormat(string) each time. This
 * test attempts to check the relative efficiency of each method.
 *
 * In multiple tests, with the below values, the results are as follows:
 *     Parsing: 4.7E7 +/- 0.2E7
 *     Format:  6.3E7 +/- 0.2E7
 *
 * In other words, thread locking appears to be fastest, but only marginally so (10,000
 * new SimpleDateFormat objects created and parsed) 
 */
public class DateUtilTest {
	private static final Object lock = new Object();

	private static final List<String> stringList;
	private static final List<SimpleDateFormat> formatList;
	static {
		stringList = new ArrayList<String>();
		for (int i = 0; i < 10000; i++) {
			stringList.add("MMMMM, dd, yyyy");
		}
		stringList.add("yyyy-dd-MM");

		formatList = new ArrayList<SimpleDateFormat>();
		for (String s : stringList) {
			formatList.add(new SimpleDateFormat(s));
		}
	}

	@Test
	public void whichWayIsFastest() {
		String dateString = "2014-04-17";

		long parsingTime = 0;
		long formatTime = 0;
		for (int i = 0; i < 100; i++) {
			parsingTime += parse(dateString);
			formatTime += format(dateString);
		}

		double averageParsingTime = Long.valueOf(parsingTime).doubleValue() / 100;
		double averageFormatTime = Long.valueOf(formatTime).doubleValue() / 100;

		System.out.println("Parsing: " + averageParsingTime);
		System.out.println("Format: " + averageFormatTime);
	}

	private static long format(String dateString) {
		long startTime = System.nanoTime();
		Date date = null;
		for (String s : stringList) {
			try {
				date = new SimpleDateFormat(s).parse(dateString);
			} catch (Exception ignore) {}
			if (date != null) {
				break;
			}
		}
		long stopTime = System.nanoTime();
		return stopTime - startTime;
	}

	private static long parse(String dateString) {
		long startTime = System.nanoTime();
		Date date = null;
		for (SimpleDateFormat dateFormat : formatList) {
			synchronized (lock) {
				try {
					date = dateFormat.parse(dateString);
				} catch (Exception e) {}
			}
			if (date != null) {
				break;
			}
		}
		long stopTime = System.nanoTime();

		return stopTime - startTime;
	}

}