Instance Method in Object-Oriented Programming

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Questions and Answers

What is the primary purpose of following naming conventions in Java?

To enforce strict coding rules

To minimize code performance

To improve code readability (correct)

To create unique identifiers

Which of the following correctly describes the way classes should be named in Java?

They should begin with an uppercase letter and be nouns. (correct)

They should be named using acronyms.

They can be any combination of lowercase letters.

They should start with a lowercase letter.

What might occur if a developer fails to follow Java naming conventions?

Improved code efficiency

Increased potential for confusion or errors (correct)

Faster compilation times

Easier code synchronization

According to Java naming conventions, which example is not a suitable class name?

button Signup and view all the answers

How do Java naming conventions suggest naming identifiers like methods and variables?

They should use camel case and describe what they do. Signup and view all the answers

Which statement about Java naming conventions is incorrect?

They are mandatory to follow. Signup and view all the answers

When naming packages in Java, which rule should be followed?

Use lowercase letters and avoid underscores. Signup and view all the answers

What is a suggested naming practice for constants in Java?

Use all uppercase letters with underscores. Signup and view all the answers

Which type of association describes a relationship where one object can have many related objects?

One to Many Signup and view all the answers

What term describes a relationship where one object must contain another object as part of its state, with dependent objects having no independent existence?

Composition Signup and view all the answers

In which programming paradigm does data hiding protect global data from being accessed freely?

Object-oriented programming Signup and view all the answers

How do object-oriented programming languages simulate real-world events more effectively?

By utilizing attributes and behaviors of objects Signup and view all the answers

What is the primary difference between object-oriented programming and object-based programming languages?

Object-based programming languages do not support inheritance. Signup and view all the answers

Which of the following statements best describes aggregation?

It denotes a weak relationship with a 'has-a' characteristic. Signup and view all the answers

Which statement accurately reflects the advantages of OOP over procedure-oriented programming?

OOP simplifies development and maintenance for larger projects. Signup and view all the answers

What type of association allows many objects to be related to multiple other objects?

Many to Many Signup and view all the answers

What is required to call an instance method in a class?

An object of the class Signup and view all the answers

Which of the following best describes an accessor method?

Reads an instance variable without modifying it Signup and view all the answers

How can an abstract method be correctly defined in a class?

It must be declared with the keyword 'abstract' Signup and view all the answers

Which method type is identified by the prefix 'set'?

Mutator method Signup and view all the answers

What characterizes a factory method?

It returns an object of its class Signup and view all the answers

What is the main purpose of the main() method in Java?

It serves as the entry point of the application. Signup and view all the answers

What is included in a method's signature?

Method name and parameter list. Signup and view all the answers

In Java, what does the 'private' access specifier indicate?

The method is accessible only within the defining class. Signup and view all the answers

What should a method name in Java typically start with?

A verb. Signup and view all the answers

What is the role of the return type in method declaration?

It signifies the type of value returned by the method. Signup and view all the answers

What characterizes the 'default' access specifier in Java?

Accessible only within the same package. Signup and view all the answers

When a method has no parameters, how are the parentheses represented?

They remain empty but are still needed. Signup and view all the answers

What is the purpose of the method body in a method declaration?

To perform all the actions defined by the method. Signup and view all the answers

What is a user-defined method?

A method created by the programmer to meet specific requirements. Signup and view all the answers

What will the output be if the number 12 is passed to the findevenodd() method?

12 is even Signup and view all the answers

How is a static method invoked?

By using the class name directly. Signup and view all the answers

Which statement is true regarding the add() method?

It returns a sum of the two integer parameters. Signup and view all the answers

In what scenario would a method be marked as void?

When it does not return any value. Signup and view all the answers

What is the main advantage of using a static method?

It can be called without creating an object of the class. Signup and view all the answers

What happens when the control reaches the findEvenOdd(num) line in a program?

The method findEvenOdd() is invoked. Signup and view all the answers

What keyword is used to define a static method?

static Signup and view all the answers

Study Notes

Object Associations

Four types of associations exist: One to One, One to Many, Many to One, and Many to Many.
One country has one prime minister (One to One); a prime minister can have many ministers (One to Many).
Many MPs may relate to one prime minister (Many to One), while many ministers can belong to many departments (Many to Many).
Associations can be unidirectional or bidirectional.

Aggregation

Aggregation is a type of association where one object contains other objects, representing a weak relationship, also known as a has-a relationship.
Enables the reuse of objects.

Composition

Composition is a stronger form of association where one object contains other objects, indicating dependent existence.
If a parent object is deleted, all child objects are also deleted.

Advantages of Object-Oriented Programming (OOP)

Simplifies development and maintenance; easier management as project sizes increase.
Provides data hiding; global data in procedural languages can be accessed anywhere.
Simulates real-world events effectively, offering solutions to real-world problems.

Object-Oriented vs. Object-Based Languages

Object-based languages include all OOP features except Inheritance (e.g., JavaScript, VBScript).

Java Naming Conventions

Naming conventions guide the naming of classes, packages, variables, constants, methods, etc.
Following naming conventions improves code readability and prevents confusion.

Advantages of Naming Conventions

Standard conventions enhance code readability, reducing time spent deciphering code.

Naming Conventions for Identifiers

Classes: Start with uppercase, are nouns, and avoid acronyms (e.g., public class Employee).
Methods: Start with lowercase, containing verbs that reflect functionality.

Method Declaration

Consists of visibility, return type, name, and arguments.
Method signature includes the name and parameter list.

Access Specifiers in Java

Public: Accessible by all classes.
Private: Accessible only within the class defined.
Protected: Accessible within the same package or subclasses.
Default: No specifier means visible only in the same package.

Method Components

Return Type: Specifies the type returned (or void if none).
Method Name: Unique identifier corresponding to functionality.
Parameter List: Contains data types and variable names.
Method Body: Contains actions, enclosed in curly braces.

User-Defined Method

Custom methods created as per requirements.

Invoking Methods

Calling a user-defined method transfers control and executes corresponding actions.

Static Method

Associated with the class rather than an instance; called without creating an object.
Commonly used for methods like main().

Instance Method

Non-static methods requiring an object of the class to be invoked.
Includes Accessor methods (getters) to read variables and Mutator methods (setters) to modify values.

Abstract Method

Declared without a body; must be in an abstract class, uses the keyword abstract.

Factory Method

Returns an object to the class; all static methods serve as factory methods (e.g., NumberFormat.getNumberInstance()).

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Description

This quiz explores the concept of instance methods in classes, focusing on non-static methods and their necessity for creating class objects. Additionally, it covers the types of instance methods such as accessor and mutator methods. Test your understanding of these fundamental programming concepts!