javadoc does not describe what this method is for.
The term "all control parameters" is used, but actually, we can pass in a subset of the control parameters, and the method would still work.
The fact that you can pass in a key, and this key does not appear in the resulting map, can be confusing. You should still put null in the resulting Map to be consistent. It is easier for the caller to find out that a key has a null value than for the caller to find out that the key does not exist in the map.
The method returns Map< > instead of HashMap< >, why?
nullin the resulting Map to be consistent. It is easier for the caller to find out that a key has anullvalue than for the caller to find out that the key does not exist in the map.