The current impl of the method is the following:

    public String getRootRelativeURL() {
String id = getParameter("id");
return (id == null ? rootRelativePath : rootRelativePath + "#" + id);
    }

There are 2 points here:

1) the efficiency of the search in getParameter() is O(log(N)) where N is the number of parameters. Consider to use HashMap to provide the O(1) sarch time.

2) the implementation each time concatenates 2 "id" parameter and "rootRelativePath".
A consequence of this is that a *new* String object is created each time.
We use the root relatibe URL as a key to find test data. And returning the same object might improve the performance very mush. Please consider to implement such improvement.
Also please consider to return a pre-cached (field) value (as well as it is done for #getRootRRelativePath()) because we use this methopd very frequently.