I had a strange error here,
A JE created and posted on the previous period (Dec 2008), an reversal was created for this same JE and posted in the same period.
But when I run the query I found JE created before was posted in Dec 2008 but the reversal was in Feb 2009.
I have checked on both JE the posting date is Dec 2008. Both the periods are unlocked.
Can someone help me to find out why the reversal posted in the current period.