To build:
    This examples uses the SizeOf library from SourceForge:
    http://sizeof.sourceforge.net/
    Download the library from that site and set
    SIZEOF=/path_to/SizeOf.jar

To run:
    java  -javaagent:$SIZEOF -jar jars/size.jar
    This produces output for various sized objects referenced in the text
    (which can vary depending on the 32-/64-bit setting of the JVM
    and whether or not CompressedOops are in use).

Example 7-2:
    Size of a, b and c classes