He can only survive for a matter of hours (he needs to breath).
Also, not only is the sun hot but the pressure is kazillons of times that of the deepest ocean. It will crush anything known in existance (if it doesn't disintegrate first).
I just thought about something. With the seemingly infinite temperature and pressure and gravity the sun has I'm very surprised Superman can survive inside of it. If that is the case then logically there should be no humanoid ever physically beating (or even harming) him period. The pressure on the Sun would easily dwarf the strongest Marvel or DC humanoid's pressure of punch.
First of all hulk adapted to space, so he doesn't need to breath, same wen he goes in to water he adapts.
He survived in some hot situations, so he might adapt to the sun who knows.
And people need to realize we are talking comics, so if some dude can walk on the sun, of course it's not real.
Try to keep comics and real live separate.
Hulk can't adapt. He has special things on him to breath under water (they came with the Hulk). Anyway marvel says he can survive in space for a matter of hours. Are they liars or the writers?
All the Hulk haters and Superman fanboys need to understand that Hulks beats flying bricks who have speed and exotic powers. So you all can't say that 90% of his fights were PIS. Also, Superman has rarely used superspeed, T-Vo, etc. in his battles (see Death of Superman). So I guess 99% of Superman's battles were CIS on his part.
When the Hulk can survive his atoms being fused together, then he may live. I don't think he can survive that though, unless he's gotten some INSANE power ups.