OOP Midterm Exam

Classification

is the process of grouping objects together based on common characteristics.

In Java, this is achieved through the use of classes and interfaces.

Classes, interfaces

_____ and _____ can be used to classify objects based on their attributes and behaviors.

Interface

is a collection of abstract methods and constants that can be implemented by a class

Interface

defines a set of methods that a class implementing that interface must provide.

methods in an interface

do not have any implementation, but only the method signatures are defined.

inheritance

Hierarchical relationship of classesi is created using _____.

child class

can inherit properties and methods from a parent class, and can also add its own properties and methods.

hierarchy of classes

This creates a _____, where each child class can inherit from its parent class, and can also be inherited by other child classes.

Generalization

is the process of creating a more general class from a more specific class.

Generalization

This allows you to create a hierarchy of classes that share common properties and behavior.

Specialization

is the opposite of generalization

Specialization

it involves creating a more specific class from a more general class.

Specialization

This allows you to add additional properties and behavior to a more specific class without affecting the more general class.

Specialization

is the act of capturing differences among objects in a class and creating new distinct subclasses with the differences.

Specialization

In this way, we are specializing information about objects of the superclass into subclasses.

Classification

categorizing objects into a class.

Classification

A subclass is a specialized class of a superclass, and a superclass is a generalized class of a subclass.

Generalization

the act of capturing similarities between classes and defining the similarities in a new generalized class

Generalization

the classes then become subclasses of the generalized class.

Specialization

the act of capturing differences among objects in a class and creating new distinct subclasses with the differences.

message

is a method call from a message-sending object to a message-receiving object.

message-sending object

is a sender

message-receiving object

is a receiver.

object

• responds to a message by executing one of its methods.

• may have as many methods as required

arguments

Additional information, known as _____, may accompany a method call.

parameterization

Such _____ allows for added flexibility in message passing

set of methods

collectively defines the dynamic behavior of an object.

object identifier, method name, arguments

A message is composed of three components

object identifier

indicates the message receiver

method name

corresponding to a method of the receiver

Arguments

additional information required for the execution of the method

method

is a program module that contains a series of statements that carry out a task.

main() method

can execute additional methods, and those methods can execute others.

class

Any _____ can contain an unlimited number of methods, and each method can be called an unlimited number of times.

calling method or client method

invokes a called method.

public,

private,

protected,

default

4 access modifiers

Return type

is a method that returns a value of a specific type after performing some operation.

return type of the method

specifies the type of the value that the method returns.

method that does not have a return type

is a method that does not return a value

method that does not have a return type

These methods are typically used to perform some operation or modify the state of an object, but they do not return any value.

void

The return type of a method that does not return a value is specified as _____

return statement

A method ends when any of the following events takes place:

The method reaches a _____.

return statement

causes a method to end and the program’s logic to return to the calling method.

return statement

frequently sends a value back to the calling method.

method’s return type

is known more succinctly as a method’s type.

Method chaining

Any method might call any number of other methods.

Client

Refers to an object that requests some operation to be performed by another object.

Client

The _____sends a message (invokes a method) to another object, asking it to perform a specific task or provide some information.

Client

is typically responsible for making the initial request and for processing any results that are returned.

Server

Refers to the object that receives and processes the message sent by a client.

Server

contains the methods that can be invoked by clients.

These methods define the behavior of the _____ object.

Server

After receiving a message, the _____ object performs the necessary operations and may return a result to the client.

Method overloading

in Java is a feature that allows a class to have multiple methods with the same name but different parameters.

Method overloading

This is useful when you want to perform the same operation with different types of data or with different numbers of arguments.

Method overloading

The compiler chooses the correct method to call based on the arguments that are passed.

parameter identifiers

do not have to be different, but the parameter lists must satisfy one or both conditions

different numbers

The lists must have _____ of parameters.

parameter data types

The lists must have _____ in different orders

Constructor overloading

in Java is a feature that allows a class to have multiple constructors with the same name but different parameter lists.

Constructor overloading

This is useful when you want to create objects with different sets of initial values or with different ways of initializing the object's state.

Constructor overloading

The compiler chooses the correct constructor to call based on the arguments that are passed.

Reference

is a type of variable that stores a memory address, which is the location of an object in the computer's memory.

reference

When you create an object in Java, the JVM allocates memory for the object and returns a _____ to that memory location.

reference variable

can be used to access the data and methods of the object it refers to.

reference

When you pass a ____ to a method, the method can modify the state of the object, and the changes are visible outside the method.

constant field

is a variable whose value cannot be changed after it is initialized.

constant field

are commonly used for values that are known at compile-time and should not be modified during runtime.

final keyword

is used to declare a variable, method, or class that cannot be changed or overridden after it is initialized.

is-a relationship

is used to describe inheritance and class hierarchies.

is-a relationship

It represents a relationship between a more general, abstract class (superclass or base class) and a more specific, concrete class (subclass or derived class).

Creating objects by instantiating those classes.

Developing classes to run as standalone applications.

Object-oriented programming involves creating classes, which can serve two main purposes:

application class

is identified by having a public static void main(String[] args) method

public static void main(String[] args) method

serves as the entry point for the application

Classes that lack main() method

are typically meant to be used by other classes that serve as applications, promoting code modularity and reusability.

main() method

a Java application can only have one _____ with the specific header public static void main(String[] args).

Creating a Class

Assign name to class

Determine what data and methods will be part of class

Class header

• Optional access modifier

• Keyword class

• Any legal identifier for the name of class

  • Uppercase camel casing (conventional identifier)

Uppercase camel

Any legal identifier for the name of class

_____ casing (conventional identifier)

Creating a Class

In Class Body

• Declaring instance

  • Attributes represent Variable

  • Declaring variable inside a class called Instance variable

Instance variable

Declaring variable inside a class called _____

static field

Shared among all instances of the class.

static field

only one copy, and it is shared by all objects of the class.

nonstatic field

Belong to individual instances (objects) of the class.

nonstatic field

Each object has its own set of this

private field

provide highest level of security to a field means that no other classes can access the field’s values, and only methods of the same class are allowed to set, get, or otherwise use private variables.

information hiding

• principle used in creating private access is sometimes called _____;

• is an important component of object-oriented programs.

Instance methods

in Java are methods that belong to an instance of a class, rather than to the class itself.

Instance methods

They are defined within a class, and can access and modify the state of the instance variables of that class

Static method

can call a static method on the class itself, without creating an object of that class.

nonstatic method

access and modify instance-specific data and variables, and their behavior can vary from one object to another.

Access Modifier

Return type

Method name

Parameter

4 Components of creating instance method

Method Body

It is a part of the method declaration.

Method Body

It contains all the actions to be performed.

Method Body

It is enclosed within the pair of curly braces.

Mutator method,

Accessor method

2 Types of Instance Method

Mutator method

is a type of instance method that is used to set or modify the value of an object's instance variable.

Mutator method

It is also known as a "setter" method because it "sets" a new value for a variable.

Accessor method

is a type of instance method that is used to get the value of an object's instance variable.

Accessor method

It is also known as a "getter" method because it "gets" the current value of a variable.

Mutator method

Define the method within the class definition.

Specify the access modifier (public, private, or protected) and any other relevant modifiers.

Specify the return type of the method. It is usually void because it doesn't return anything.

Specify the method name, using a naming convention like setVariableName() to indicate that it is a ____ method.

Write the code for the method inside curly braces to set the new value for the variable.

Accessor method

Define the method within the class definition.

Specify the access modifier (public, private, or protected) and any other relevant modifiers.

Specify the return type of the method to match the data type of the variable you want to retrieve.

Specify the method name, using a naming convention like getVariableName() to indicate that it is an _____ method.

Write the code for the method inside curly braces to return the value of the variable.