Why does a singleton object take more bytes?

[yulunz]

Hi,

Maybe a noob question, but I am interested to learn why a singleton object of the same type takes more space?

memory-measurer/ElementCostInDataStructures.txt

Line 47 in 19bfa23

Singleton ArrayList :: Bytes: 40.00, Obj: 2.00 NonNull: 2.00 Null: 0.00 scalars: [int x 2]

Thanks!