well theres a few problems with this, and
this is the main problem
calls to this/super can only be made in constructors, and it has to be the first line of code, you tried to do it based on what your if returned to you.
to get around this you could do the following
problem with that is contructors dont return any thing, so you'll get something like this printed out "Test@1".
now to get around that you can print your output in the constructor.
now that will return the result you're looking for, alternatively you could use constructors for what they're intended for, to construct/initialiase your objects, and put your calculations into methods