Memory usage

For a typical 64 bit machine

Primitive Types

         

Object

      Object size = total size of instance variable + Object overhead (16 bytes) + Padding

      Padding = Memory usage padded to multiple of 8 Bytes ( Padding speeds up memory                                                                                                       access & garbage collection)

     

ex: 16 Bytes + 4 Bytes + 4 Bytes (for multiple                                                       of 8 Bytes)

References: A reference to an object typically is a memory address and thus uses 8 bytes of memory

Inner Class: A nested non-static (inner) class such as our Node class requires an extra 8 bytes of overhead (for a reference to the enclosing instance).

Arrays: An array of primitive-type values typically requires 24 bytes of header information plus the memory needed to store the values