http://mail.openjdk.java.net/pipermail/valhalla-dev/2018-June/004450.html

Unsafe::getObject returns a reference to an object. Similarly Unsafe::putObject sets a reference in the given base+offset. It's proposed to rename Unsafe xxxObject to xxxReference that will make the API very clear xxxReference are getters/setters for a reference (instance of object class). In the future getters and setters for values would be named xxxValue.

When we have value types: A reference can refer to an object (instance of object class) or a value (instance of a value class), or it can be null. Value flattening is a storage tactic which must be detected in a given array class or field; otherwise, it’s all about simple pointer-shaped references.