The JVM specification does not specify anything about how objects should be represented. The only time internal representation of objects is discussed in the JV

The JVM specification does not specify anything about how objects should be represented. The only time internal representation of objects is discussed in the JVM spec is section that says "The Java Virtual Machine does not mandate any particular internal structure for objects." In this case the JEP is scoped to just the hotspot runtime. Other implementations are free to represent objects however they want. https://docs.oracle.com/javase/specs/jvms/se23/html/jvms-2.html#jvms-2.7 https://docs.oracle.com/javase/specs/jvms/se23/html/jvms-2.h...