how to get the assigned date and time, done date and time for a particular task in bonita bpm 7.0.3 using external API?
This was answered before here
you have to look at the case information, or for one that has been completed the ArchivedProcess.
The API's are all described in the Javadoc in the documentation.
Please also note: repeat questions will not get you an answer quicker, and it helps if you can show what you have done so we can help you,