The parameter has limited scope. It is similar to a local variable, in that is exists only for the duration of the execution of the method. Once the method is exited from (a return is executed or the end of the method is reached), the variable no longer exists. Your line 3 assigns the value of that variable to an instance field where its scope is less limited. It will exist for as long as that instance exists.

Thanks. That makes perfect sense. Is there documentation of standards on naming different type of variables? I added the "P" because this was a parameter.

Not really. It mostly is up to the programmer. Oftentimes, the same name as the field will be used as follows: Other times, you might see an underscore being used: If you were to add complete documentation and "publish" the class, you may be "forced" to specific naming so that the documentation makes sense and is easy to follow.