Do you mean primitive type array? Because in that case, a bunch of arrays of primitives does not have the same layout and cache locality as an array of structs of primitives.
Layout within objects is not what I'm talking about here. What I'm talking about is layout of objects within an array. There's no way to do an array of <whatever>. It's an array of <primitive> or an array of <pointer to whatever>. So much pointer-chasing!
In (e.g.) C, I can do either array-of-structs or structs-of-arrays. In Java... I don't know any way to have an array-of-structs in Java (portably, that is).
