Here is the Fix.
I had faced the issue twice.
For the first time when i encountered this issue,i had to increase the JTA timeout for the failing Data-source from default value to 1200(some greater value),i followed below steps,
1. Login to weblogic console
2. Goto Services > JTA
3. Open Configuration > JTA
4. Increase the "Timeout Seconds" value
On restarting the managed servers,the issue was solved.
But,Second time(scenarios were different related to soa workflows/composite),the issue was very similar and its resolution was same as above,and that I have already tried.But below solution have saved my time :
1. Click DataSources under Service
2. Select the Datasource(you can pick the name from exception),in my case SOADataSource.
3. Go to Configuration > Transaction.
4. Check the checkbox "Set XA Transaction Timeout".
Restart the servers targeted to run on this Datasource.