What is the difference between 'finished' and 'completed'?

What is the difference between 'finished' and 'completed', As both words gives the same meaning.

Ex 1: He finished his homework.

Ex 2: He completed his homework.

And also how to use or where to use these words ?

Dictionary Reference :

Completed : Finish making or doing.

Finished : Brought to an end; completed.

As for me both sentence has same or mere meaning, So is there any real difference between?

Solution 1:

I could see a subtle difference. I always though the difference was this:

completed - means you've done all the parts of the relevant task
finished - you have done the task as a whole, but you may have skipped some parts.

Example:

I have finished the game, but I'm yet to complete all the side quests.

Edit: Free Dictionary agrees with me

Complete
1. Having all necessary or normal parts, components, or steps; entire: a complete medical history; a complete set of dishes.

Finish
a. To stop (doing an activity or task) after reaching the point at which there is nothing left to do: finished cleaning the room.
b. To bring to a required or desired state: finish an assignment; finish a painting.

Solution 2:

Finished implies the actor state. Complete refers to the task state. Halfway through a marathon, a runner can be finished with the race and go home. The runners that completed the marathon have run its entirety.

Politically, a politician could be 'finished' if an egregious error were committed. However, it would be incorrect to say the politician was 'completed'. To complete a term implies success.

This is why waiters will ask 'are you finished' with a meal, especially when it is incomplete. A waiter asking 'are you complete?' would be asking an entirely different question that would have deep philosophical implications.

This demonstrates that the actor is finished (runner, politician, consumer) but the task is completed (marathon, election term, meal).