The JDWP/JDI canUnrestrictedlyRedefineClasses capability is not compatible with the JVM TI spec as the JVM TI does not allow unrestricted class redefinition. It is why this capability is always false in the reference implementation of the JDI. We have to deprecate this capability (and related access methods) or make it clear somewhere that it returns always false in the reference implementation.

Similarly for the canAddMethod capability.

For JDWP protocol details, please, see the JDWP CapabilitiesNew command (VirtualMachine command set) spec:
  https://docs.oracle.com/en/java/javase/11/docs/specs/jdwp/jdwp-protocol.html#JDWP_VirtualMachine_CapabilitiesNew