As I've acknowledged there's been a fair amount of verbal harassment (and obnoxious signage), some of it arguably antisemitic. Deplorable thought it is, it gets into a different topic (from the issue of people being supposedly blocked from campus areas due to their perceived ethnic classification).
It's also not been a feature of the encampments as such that I'm aware of (but I could be wrong of course). More like a feature of spontaneous confrontations / street actions.
Addendum (edit): To the extent that some of these people protest Israel specifically (as no doubt many of them do) -- it's usually against Israel in its current (effectively Revisionist) Zionist configuration, aka "Israel as a rigidly defined ethnostate", built on as much territory as it can reasonably hold onto and with a supremacist attitude towards non-Jewish inhabitants. Not the "legitimacy of a Jewish homeland" in principle, which can mean a lot of things (such as the idea of a "Jewish homeland" that is genuinely democratic and not determined by the fact of a Jewish supermajority).