What is the difference between ...?

Question

What is for example the difference:
1.:
if(a+b)
2.:
if((a+b))

i mean generally, i see often that they do another Bracket around statements why?

Answer 1

I don't think you can add booleans like that and java has some dignity to not have implicit casts from integer (or other type) to bool. So what a+b is supposed to mean?

Answer 2

ok that was wrong, because i didn't understand it
sometimes they do if((statement))