CMSC132 Study Guide 3. Questions and Answers 100% Correct

CMSC132 Study Guide 3

What methods are in the Comparable interface? – answer compare To()

What methods are in the Comparator interface? – answer compare()

You cannot instantiate an abstract class. - answer True

An abstract class allows inheritance. - answer True

An abstract class is useful for polymorphism - answer True

If a class contains an abstract method then the class must be declared as abstract -
answer True

If a class is declared as abstract then the class must contain at least one abstract
method - answer False

Code inside the abstract class can make calls to methods of the class that are declared
abstract - answerTrue

A concrete (non-abstract) class extending an abstract class must provide
implementations for the abstract methods of the class - answerTrue

An abstract class can be used as a type - answerTrue

An abstract class can be used as the type for a "polymorphic collection" - answerTrue

Name an advantage of using interfaces over abstract classes - answerAn advantage of
interfaces is that you can implement as many interfaces as you want in a class.

Name an advantage of using abstract classes over interfaces - answerAn advantage of
abstract classes is inheritance.

You should be prepared to write Junit tests -
answerhttp://www.cs.umd.edu/eclipse/JUnitTesting.html

When should you "throw" an exception? - answerWhen an exceptional event has
occurred that might break your code

Describe Java exception handling in detail. Be sure to mention "throw", "catch", and the
role of the call stack. - answer-pops off each stack until it finds catch block, if not
terminate program, will not run code until it find catch block.