Code Tools: jol
See the JOL Source Repository for additional details.
JOL (Java Object Layout) is the tiny toolbox to analyze object layout schemes in JVMs. These tools are using Unsafe, JVMTI, and Serviceability Agent (SA) heavily to decoder the actual object layout, footprint, and references. This makes JOL much more accurate than other tools relying on heap dumps, specification assumptions, etc.
