In reply to shanthi:
In reply to UVM_LOVE:
All the uvm component constructors will be expecting two arguments (string name, which is used to refer the component & uvm_component parent, which gives the information about who is creating the component) similar to the constructor you mentioned in test class.
For TB the parent will be the test as test is creating the tb, and handle name itself will be used as string to refer the tb. But in the build phase of test while calling the constructor of TB you did not pass the value for those arguments so you are getting the error, it is mandatory to pass those arguments as in case1
In UVM you have to create the components & objects using the factory method create , it is not recommended to create by calling the constructor directly
Sorry this is not an answer what I want.