Nothing will happen if it is a constitutional secular democracy, in the ideal state I talked about. A secular state is not possible without the people agreeing to it and if the people agree to it, and such a state is formed, nothing will happen to the Jews. Jews are a minority here as well, and nothing happens to them. They were a minority in Muslim majority countries before Israel was formed, even under Islamic dictatorships and kingdoms, and nothing happened to them. Infact, you know where they were unsafe? In Europe. The "free" world, where 6 million of them got slaughtered.
That said, this is an ideal state, so it is not going to happen.
Before the formation of Israel, both Arabs and Israelis were forming their own respective militant groups and massacring each other. The whole modern zionism thing started with Herzl's publication of Der Judenstaat in 1896. Before that Jews were living peacefully in the middle east as minorities, amongst Muslims and the only place where they had problems was in Europe. So the formation of Israel was NOT legitimate. Israel should not have been formed in the first place. It was a classic case of colonial paper partition where the UK took land that did not belong to it and gave it to a people, who did not live there for the most part without consulting the local population there.
But TODAY it is a legitimate state, the same way Canada and the US are. Canada and the US were also formed via colonization of Native American land. But now, they are legitimate states, as enough time has passed. Similarly, Israel today is recognized, and people there have an identity etc., But not when it was formed. That was solely religiously driven nationalism and it was very unfair to the local population. "We lived here 2000 years ago" is not a legitimate argument. If it was, it would be legitimate of Native Americans to acquire superior weapons, and drive us all out of our homes, because they were here before us lol.