Object-Oriented Class Design

Question 1

Keywords in object-oriented languages that set the accessibility of classes, methods, and other members. The two most common are private and public, where private limits access only to members of the class, and public grants open access.

Answer 1

Access Modifier

Question 2

Method in Java that allows and controls access to private data of objects.

Answer 2

Accessor Method

Question 3

A process in class definition that acts on the data that belongs to that class.

Answer 3

Class Method

Question 4

A variable that belongs to the class, and is not specific to any particular object, indicated by the word “static,” of which only a single copy exists, regardless of how many instances of the class exist.

Answer 4

Class Variable

Question 5

The process of instantiating (bringing into existence) an object based on a class definition.

Answer 5

Construct

Question 6

A method in a class definition whose sole responsibility is to construct a new object. Classes have many versions of these, a key feature of polymorphism.

Answer 6

Constructor

Question 7

For variables in a class, this is a value that is automatically assigned, like zero for numeric variables, null for objects, false for Boolean.

Answer 7

Default

Question 8

This is the constructor either supplied by the compiler where all instance variables received default values, or one defined explicitly in the class that receives no parameters and assigns beginning values for each instance variable.

Answer 8

Default Constructor

Question 9

In a programming project, this is the class that contains the method where program execution begins, such as the main method in Java.

Answer 9

Driver Class

Question 10

A member of its enclosing class. Non-state inner classes have access to other members of the enclosing class, even if they are declared private.

Answer 10

Nested Class

Question 11

The Java reserved word that instantiates an object.

Answer 11

New

Question 12

The name of the Java class that is the “mother” of all objects. All other Java class automatically inherit this class at the top-level parent class in the hierarchy. This class provides basic methods such as the toString, hasCode, and equals methods.

Answer 12

Object Class

Question 13

This is the super class in a class hierarchy inheritance system. In Java, the Object class is the ultimate version of this class.

Answer 13

Parent Class

Question 14

Methods that belong to the String class that act on the string, such as length(), substring(), indexOf(), charAt(), etc.

Answer 14

String Methods

Question 15

An object in programming that references a String.

Answer 15

String Object

Question 16

A class whose definition inherits the characteristics of another class, called the parent class or super class.

Answer 16

Subclass.

Question 17

The reserved word in programming that designates a method or data item that belongs to the parent class, or super class.

Answer 17

Super

Question 18

The class whose characteristics are inherited by another class that inherits it, called the sub class.

Answer 18

Superclass