Вильчинский - Лабораторная работа #2

@borodulina @ryabenko please review
Yes, I googled yesterday. Of course, I might understand incorrectly.
https://docs.oracle.com/javase/tutorial/java/javaOO/methodreferences.html
https://docs.oracle.com/javase/8/docs/api/java/util/function/Supplier.html
I know about the pattern Command but this code seems to be more cleaner with method reference.