This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Agree with David Newton; you haven't actually told us what the problem is.
Your class has an overridden toString method which appears to work. You ought to declare it as . . . classMapTest<K, V> . . . but your class seems not to fulfill the test of "a MapTest IS-A HashMap". And as Vijitha Kumara said, the toString method will be wrong whenever one of your friends has a birthday!