vmcj/cloning is a SAP Parameter attribute which is used to control activate cloning for java vms information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
The option specifies whether the VM cloning should be activated if
all prerequisites are fulfilled.
The prerequisite for VM cloning is the extended memory mapping
implementation
See SAP Parameter Documentation for full SAP documentation for this profile parameter.