Finally, profiling objects that make use of java.lang.ref.* references can lead to confusing results (e.g., results that fluctuate between repeated sizeof() calls on the same object).

Introduction. In the last year or two, interest in "alternative" languages on top of the Java Virtual Machine has grown exponentially, to the point where three languages were blessed with official ...

In other words, if you imagine java.lang.Object‘s behaviors being changeable at that level, that’s what JavaScript’s Object.prototype allows. Avoiding JavaScript’s ubiquitous global scope.