I use IntelliJ on OpenBSD no problems (had to google some env var to set to make it render properly as I use a tiling window manager, apart from that it "just works").

One thing I do notice is OpenBSD's malloc implementation is much more serious about killing misbehaving apps so occasionally a process which does something it would get away with on linux/other will be taken out the back and lined up against the wall -- that's a feature and not a bug though (and configurable)