CPT 236 Test 3 Review

What modifier should you use on a class so that a class in the same package can access it but a class (including a subclass) in a different package cannot access it?

• public

• private

• protected

• Use the default modifier

Polymorphism means ______________.

• that data fields should be declared private

• that a class can extend another class

• that a variable of supertype can refer to a subtype object

• that a class can contain another class

Inheritance means ______________.

• that data fields should be declared private

• that a class can extend another class

• that a variable of supertype can refer to a subtype object

• that a class can contain another class

Encapsulation means ______________.

• that data fields should be declared private

• that a class can extend another class

• that a variable of supertype can refer to a subtype object

• that a class can contain another class

You can create an ArrayList using _________.

• new ArrayList[]

• new ArrayList[100]

• new ArrayList<>()

• ArrayList()

What modifier should you use on the members of a class so that they are not accessible to another class in a different package, but are accessible to any subclasses in any package?

• public

• private

• protected

• Use the default modifier.

Suppose an ArrayList list contains {"red", "green", "red", "green"}. What is the list after the following code?

list.remove("red");

• {"red", "green", "red", "green"}

• {"green", "red", "green"}

• {"green", "green"}

• {"red", "green", "green"}

What is the output of the following code:

public class Test {

   public static void main(String[] args) {

     Object o1 = new Object();

     Object o2 = new Object();

     System.out.print((o1 == o2) + " " + (o1.equals(o2)));

   }

}

• false false

• true true

• false true

• true false

Invoking _________ removes all elements in an ArrayList x.

• x.remove()

• x.clean()

• x.delete()

• x.empty()

• x.clear()

Which of the following is incorrect?

• A constructor may be static.

• A constructor may be private.

• A constructor may invoke a static method.

• A constructor may invoke an overloaded constructor.

• A constructor invokes its superclass no-arg constructor by default if a constructor does not invoke an overloaded constructor or its superclass's constructor.