Question

Question 60.1 pts

Which of the following is true about a concrete class?

A concrete class may be extended.

A concrete class may be instantiated.

A concrete may NOT contain abstract methods.

All of the above.

None of the above.

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Question 70.1 pts

Which of the following is true?

A class extends exactly one other class and may implement any number of interfaces.

A class may extend at most one concrete class, may extend any number of abstract classes, and may implement any number of interfaces.

A class may extend one concrete class and also one abstract class, and may implement any number of interfaces.

A class may extend exactly one other class, OR may implement any number of interfaces, but not both.

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Question 80.1 pts

Given the following declarations,

public class Parent { ... }
public class Child extends Parent implements Wizard { ... }
public class Grandchild extends Child { ... }

Which of the following is NOT true?

Child "Is-A" Wizard

Parent "Is-A" Wizard

Grandchild "Is-A" Child

Grandchild "Is-A" Parent

Grandchild "Is-A" Wizard

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Question 90.1 pts

Given the following definition:

public class Alpha implements Freezable {...}

And the following client code:

Freezable f = new Alpha();

Which is true?

The variable f has static type Freezable and dynamic type Freezable

The variable f has static type Freezable and dynamic type Alpha

The variable f has static type Alpha and dynamic type Alpha

The variable f has static type Alpha and dynamic type Freezable

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Question 100.1 pts

Which of the following creates a new data type?

an abstract class definition

a concrete class definition

an interface definition

All of the above.

None of the above.

Answer 1

1)  All of the above.
2)  A class extends exactly one other class and may implement any number of interfaces.
3)  Parent "Is-A" Wizard
4)  The variable f has static type Freezable and dynamic type Alpha
5)  a concrete class definition