[LANG-478] StopWatch does not resist to system time changes

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.3
• Fix Version/s: 3.0
• Component/s: lang.time.*

Environment

all operating systems.

• Assignee: Unassigned
• Reporter: Regis Desgroppes
• Created: 09/Jan/09 10:12
• Updated: 17/Dec/09 03:45
• Resolved: 01/Mar/09 21:18

Description

org.apache.commons.lang.time.StopWatch seems to be relying on wall clock, i.e. by calling java.lang.System.currentTimeMillis() to sample current time.

When a system time change occurs (user action, NTP synchronization...) between 2 calls to StopWatch.getTime(), the difference between the 2 samples is wrong: the measured duration may noticeably differ from the real one. Moreover, should the system time change consist in a backward adjustment, the difference could be negative.

In order to make StopWatch resistant to system time changes, would it be possible to use the process time, i.e. by making implementation calling java.lang.System.nanoTime() -multiplied by appropriate factor, of course.

Thanks a lot,
Regis.

Issue Links

• duplicates: LANG-323 StopWatch: increase precision by using System.nanoTime()