When I was little people told me that ending minor piece in major is a feature of the Bach style.
What they probably meant is the Baroque style (not too many people played the Renaissance music in my childhood in my neighborhood).
That's true, isn't it?
Otherwise, it sounds like Mendelssohn.
So what's the meaning of such an ending?
I remember people wondering maybe it's a feature of optimism in early times. Even the sad stories end well.
But in reality it's probably more simple than that.
You see, keyboard instruments in the Renaissance and Baroque times were tuned based on pure major thirds (without the beats). Some temperaments had more of them than others.
So the idea of the last chord of the piece being major derives from the tuning systems of the time - in a major chord (like C-E-G), the first third is major (C-E). Therefore, more pure.
This third is called Picardy Third.