Warning: spoilers for Superman: Son of Kal-El #1!
The new Superman has officially proved he can stop the Incredible Hulk - but with a new method that involves more than a simple punch. Jonathan Kent takes over his father's legendary name in Superman: Son of Kal-El #1, written by Tom Taylor with art by John Timms and colors by Gabe Eltaeb. He faces a busy first day on the job, in which he fights a natural disaster, the United States military, and a frightened metahuman with fire-based powers beyond his control.
Jonathan Kent has all of his father's powers but considerably less experience, and is relatively untested when it comes to solo superheroics. Just like Clark Kent, Jonathan has vowed to protect the Earth and all who live there; indeed, he wants the House of El family crest on his chest to stand for "Truth, justice, and a better world." While helping evacuate civilians during a massive wildfire in California, Superman comes across a new, out-of-control threat, surrounded by soldiers.
Superman reasons that such a massive fire still required a spark, and he finds it in the form of an unnamed metahuman producing flame at an alarming rate. He's surrounded by the military who continue to open fire, even as their bullets melt before reaching their target. Superman intercepts an inbound missile and swoops into the inferno, placing himself between the soldiers and the metahuman, who's clearly scared out of his wits. Scanning the man using his X-ray vision, Superman sees his pulse spiking. "Your heat is connected to your stress levels," he says "and being on fire and under attack from the military looks pretty stressful." With that, Jonathan hugs the man and the flames slowly die out.
With this act, Jonathan Kent proves he's more than worthy of the name Superman. Walking into literal flames to calm someone down is the mark of a true hero - and it's also the one tactic that can successfully calm down the Hulk without resorting to blows. In the Marvel Universe the supremely-powerful Sentry is one of very few heroes who can also stop the Hulk in this manner; though his physical strength is impressive, it's his kindness and calming nature that allows him to stop an angry Hulk.
It's worth noting that Superman and the Hulk have met before, but they mostly let their fists do the talking. Jonathan is not his father, and wants to make his own legacy; calming down a pyrokinetic metahuman instead of attacking him is a good indicator of his true intentions. Just like the Sentry, Jonathan is as empathetic as he is physically strong. Should the Hulk and this new Superman ever meet, it's likely that Jonathan will do whatever he can to deescalate a potential fight.