Weird Date parsing error in Java

Question

While parsing a large number of dates in java, I occasionally get this weird bug :

java.lang.NumberFormatException: For input string: ".201144E4.201144E4"
    at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1250)
    at java.lang.Double.parseDouble(Double.java:540)
    at java.text.DigitList.getDouble(DigitList.java:168)
    at java.text.DecimalFormat.parse(DecimalFormat.java:1321)
    at java.text.SimpleDateFormat.subParse(SimpleDateFormat.java:1793)
    at java.text.SimpleDateFormat.parse(SimpleDateFormat.java:1455)
    at java.text.DateFormat.parse(DateFormat.java:355)
    at gameloop.tf2tradebot.user.UserManager.getUser(UserManager.java:102)
    at gameloop.tradebot2.bot.weaponbot1.Weaponbot1.onMessageReceived(Weaponbot1.java:269)
    at gameloop.api.steam.chat.ChatEvent.run(ChatEvent.java:49)
    at java.lang.Thread.run(Thread.java:745)

I this case, the date was

2014-12-13 06:56:27

The date format was

private static final DateFormat STANDARD_DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.ENGLISH);

My code:

Date firstSeenDate = null;
try
{
    firstSeenDate = STANDARD_DATE_FORMAT.parse(firstSeen);
}
catch(Exception pe)
{
    pe.printStackTrace();
    logger.outputError(4001, "Error parsing first seen date. Shutting down...");
    logger.outputError(4001, "First seen date : \'" + firstSeen + "\'");
    CH405BotServer.shutdown(logger.getCallerName(), "an error in parsing first seen date");
}
user.setFirstSeen(firstSeenDate);

Source data :

isadmin = false
firstseen = 2014-12-13 06:56:27
lastseen = 2014-12-13 06:56:27
numtrades = 0

EDIT : The string in the error log seems perfectly fine :

(ERROR 4001) Error parsing first seen date. Shutting down...
(ERROR 4001) Last seen date : '2014-12-13 06:56:27'

I need help on how to solve this.

Answer 1

I suspect it is caused by race condition, SimpleDateFormat is not thread-safe and if multiple threads tries to parse Date from String to Date using same isntance it could mess up internal state of that instance

I would suggest either using local variable (warn: it is expensive to create this instance), so if you think it is too frequent, you can use FastDateFormat (thread-safe implementation of SimpleDateFormat) or as @Ray suggested switch to Java8