list, map and put of the Queue in the Tree Data Structure

[jefsummers]

OK, but the first problem is that the list is created but then discarded. You need to assign the list to a variable, or print it, or do something with it as in the other posts above. Otherwise the only true function of that line is to throw an exception if the data does not fit. In other words, it is a data test but the result is not kept.