The problem with Java off-heap designs compared to C is that many Java language features become useless (e.g. instance variables, polymorphism, ...) and you lose the standard library as well as almost every single third party library out there.
In my view, sun.misc.Unsafe is extremely unproductive to work with. But I will say that it may be the right solution for adding a small very spcialized feature to a larger Java application.
In my view, sun.misc.Unsafe is extremely unproductive to work with. But I will say that it may be the right solution for adding a small very spcialized feature to a larger Java application.