The error occurs, because vijava and your chosen fork yavijava are trying this:
SERVICE_INSTANCE_MOR.set_value("ServiceInstance");
The problem is the following:
That code tries to use the method ManagedObjectReference.set_value(String) and the jar comes with that class included.
If you added the default vim25.jar from VMware it also includes this class with the exact same name and package path.
Now some part has to decide which of these two classes its gonna use when that method gets called, but they're not identical. The vim25-version instead of set_value(String) has the method setValue(String). So if whatever part decides to use the vim25-version, the method set_value(String) is not existing and throws your error.
So in short: make sure that you dont use vijava/yavijava and vim25 in the same project.
