Xia Yun created LANG-1641:
-----------------------------
Summary: Over Stack Issue
Key: LANG-1641
URL: https://issues.apache.org/jira/browse/LANG-1641
Project: Commons Lang
Issue Type: Bug
Components: lang.time.*
Affects Versions: 3.7
Reporter: Xia Yun
{code:java}
//this is the demo
package com.wcs233;
import java.util.Date;
import java.util.TimeZone;
import org.apache.commons.lang3.time.DateFormatUtils;
import org.apache.commons.lang3.time.FastTimeZone;
public class GmtTimeZoneIssue {
public static void main(String[] args) {
final String timeZoneString = "GMT+7:00";
final String ISO8601_DATE_FORMAT = "yyyy-MM-dd'T'HH:mm:ssZZ";
for (int i = 0; i < 100; i++) {
Date date = new Date();
TimeZone timeZone = FastTimeZone.getTimeZone(timeZoneString);
String dateString = DateFormatUtils.format(date,
ISO8601_DATE_FORMAT, timeZone);
System.out.println(dateString);
}
}
}{code}
when running the code above , there is over stack risk
1. When invoking FastTimeZone.getTimeZone(timeZoneString), a new GmtTimeZone
will be created
{code:java}
GmtTimeZone(final boolean negate, final int hours, final int minutes) {
if (hours >= HOURS_PER_DAY) {
throw new IllegalArgumentException(hours + " hours out of range");
}
if (minutes >= MINUTES_PER_HOUR) {
throw new IllegalArgumentException(minutes + " minutes out of
range");
}
final int milliseconds = (minutes + (hours * MINUTES_PER_HOUR)) *
MILLISECONDS_PER_MINUTE;
offset = negate ? -milliseconds : milliseconds;
zoneId = twoDigits(
twoDigits(new StringBuilder(9).append("GMT").append(negate ? '-' :
'+'), hours)
.append(':'), minutes).toString();
}
{code}
the every GmtTimeZone instance , the zoneIds instance are different , even
through the values are the same.
2. When invoking DateFormatUtils.format(), there is a ConCurrentHashMap in
FormatCache with key is MultipartKey. when invoking FormatCache.getInstance(),
first get from cInstanceCache, if value is null, putIfAbsent, but because
GmtTimeZone instances are different, when invoking GmtTimeZone.equals, the
logic is
{code:java}
@Override
public boolean equals(final Object other) {
if (!(other instanceof GmtTimeZone)) {
return false;
}
return zoneId == ((GmtTimeZone) other).zoneId;
}
{code}
every zoneId address are different so, equals function return false, but
actually the zoneId values are the same.
so FastDateFormat will be put into cInstanceCache in FormatCache again and
again, which will increase the capability of the map, and cause over stack
risk, also, it will cause application run much slower.
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