Chapter 4

Question 1

What does the class header contain?

Answer 1

• An optional acess specifier
• The keyboard class
• Any legal identifier

Question 2

What is a public class?

Answer 2

• Accessible by all objects
• Can be extended as a basis for another class

Question 3

What are data fields?

Answer 3

The data components of a class

Question 4

What are instance variables?

Answer 4

• Nonstatic fields in a class
• One copy exists for each object instantiation
• Each object gets its own copy of each nonstatic data field in its class

Question 5

What is private access?

Answer 5

• No other classes can access the field’s values
• Only methods of the same class are allowed to use private variables

Question 6

What is information hiding?

Answer 6

• Principle used in creating private access
• Private data can be change only by a class’s own method

Question 7

What are mutator methods?

Answer 7

• Set or change field values
• Called setters
• Start with prefix set

Question 8

What are accessor methods

Answer 8

• Retrieve values
• Called getters
• Start with prefix get

Question 9

What are class fields

Answer 9

Static data fields

Question 10

What is an abstract data type?

Answer 10

• A class you create
• Implimentation is hidden and accessed through public methods
• Also called programmer-defined data type

Question 11

How many copies of nonstatic methods in a class are stored?

Answer 11

• Just one

Question 12

What is a library of classes?

Answer 12

• A package or folder that groups like prewritten classes together
• Java.lang includes fundamental classes and is automatically imported into every program