Deck 8: Objects and Classes

Question 1

_________ returns the last character in a StringBuffer variable named strBuf?

Answer 1

D

Question 2

________ is invoked to create an object. A. The main method
B) A method with a return type
C) A method with the void return type
D) A constructor

Answer 2

D

Question 3

What is the output of the following program?

Answer 3

D

Question 4

Given the declaration Circle[] x = new Circle[10], which of the following statement is most accurate.

A) x contains an array of ten int values.
B) x contains a reference to an array and each element in the array can hold a Circle object.
C) x contains an array of ten objects of the Circle type.
D) x contains a reference to an array and each element in the array can hold a reference to a Circle object.

Question 5

Analyze the following code. A. The program has a compile error because x has not been initialized. B. The program has a compile error because test is not initialized.
C) The program has a runtime NullPointerException because test is null while executing test.x.
D) The program has a compile error because you cannot create an object from the class that defines the object.
E) The program has a compile error because Test does not have a default constructor.

Question 6

What is the printout for the third print statement in the main method? A. j is 3 B. j is 2
C) j is 1
D) j is 0

Question 7

Analyze the following code: A. The program compiles and runs fine. B. The program has no compile errors but will get a runtime error because radius is not initialized.
C) The program has compile errors because the variable radius is not initialized.
D) The program has a compile error because a constant PI is defined inside a method.

Question 8

When invoking a method with an object argument, ___________ is passed. A. a copy of the object
B) the object is copied, then the reference of the copied object
C) the reference of the object
D) the contents of the object

Question 9

What is the value of myCount.count displayed?

A) 99
B) 101
C) 100
D) 98

Question 10

A. 0 B. 2
C) -2
D) -1
E) 1

Question 11

Analyze the following code. A. The program has a runtime error because s is not initialized, but it is referenced in the println statement. B. The program has a compile error because s is not initialized, but it is referenced in the println statement.
C) The program has a runtime error because s is null in the println statement.
D) The program compiles and runs fine.

Question 12

Given the declaration Circle x = new Circle(), which of the following statement is most accurate. A. x contains an object of the Circle type.
B) You can assign an int value to x.
C) x contains a reference to a Circle object.
D) x contains an int value.

Question 13

Analyze the following code:

A) The program has compile errors because the variable radius is not initialized.
B) The program compiles and runs fine.
C) The program has no compile errors but will get a runtime error because radius is not initialized.
D) The program has a compile error because a constant PI is defined inside a method.

Question 14

Analyze the following code: A. The program has a compile error because you cannot assign radius to radius. B. The program will compile, but you cannot create an object of Circle with a specified radius. The object will always have radius 0.
C) The program does not compile because Circle does not have a default constructor.
D) The program has a compilation error because it does not have a main method.

Question 15

Analyze the following code: A. The program compiles and runs fine. B. The variable t is private and therefore cannot be accessed in the main method.
C) The variable x is not initialized and therefore causes errors.
D) t is non-static and it cannot be referenced in a static context in the main method.
E) The variable t is not initialized and therefore causes errors.