Introduction to Camel case in Java

In Java programming, Camel Case is a convention used to name variables, methods, and classes. It involves writing compound words or phrases where each word begins with a capital letter except for the first word, which starts with a lowercase letter. For example, “camelCaseExample” where “camel” begins with lowercase letters and “CaseExample” starts with an uppercase letter. Since the capital letters in the middle of the identifier look like camel humps, so, it is known as the camel case naming convention.

CamelCase is widely adopted in Java development because it enhances readability and makes code easier to understand. By following this convention, developers can quickly distinguish between different parts of a name and improve code consistency. Adhering to CamelCase conventions is important to maintain code quality and facilitate collaboration within a development team.

Programming languages use a naming convention called CamelCase. The Java programming language uses it to write the names of variables, constants, methods, classes, packages, etc. Only the first letter of each other word should be in capital letters; all other letters should be in lowercase. Each word, except the first one, starts with a capital letter. For example, “emailAddress” where “email” begins with lowercase letters and “Address” starts with an uppercase letter. Since the capital letters in the middle of the identifier look like camel humps, so, it is known as the camel case naming convention.

Introduction to Camel case in Java

Key takeaways

Camel case is a naming convention used for identifiers, i.e., method names, variables, etc.
Each word in the identifier begins with a capital letter. But except for the first word, which starts with a lowercase letter.
It provides more readability and consistency in the code.
Camel Case convention applies to naming classes, variables, methods, and other elements in programming.
Programmers often use Camel Case in programming languages such as Java, JavaScript, and C#.
There are two ways of using camel cases: UpperCamelCase (also known as PascalCase) and LowerCamelCase.

Understanding Camel Case Conventions

Since we can not use spaces while naming variables, methods, classes, and interfaces, we utilize the camel case concept to name them with proper word meanings. Programmers, web developers, and system administrators use camel cases in URLs, programming, and computer naming conventions.

There are two camel case conventions: lower camel case and upper camel (Pascal) case. Pascal is a person’s name, which always begins with a capital letter. In contrast, ‘camel’ is a lowercase noun unless it begins a sentence.

Explained as follows below :

1. Lower Camel Case

In lower camel case, the first character of the identifier is in lowercase. And subsequent words start with uppercase letters. Programmers use [convention] to name variables and methods.

For example: firstName, lastName, actionEvent, printArray(), etc.

You can generate lower camel cases using Java programs. You need to delete the spaces between words. Capitalize the first letter of each word (except the first word) and lowercase the remaining characters.

This is a Java implementation of the above concept:

public class StringConverter {
    static String convertStringToLowerCamelCase(String inputString) {
        // Split the input string by spaces
        String[] words = inputString.split("\\s+");        
        // Concatenate the words with proper capitalization
        StringBuilder result = new StringBuilder(words[0].toLowerCase());
        for (int i = 1; i < words.length; i++) { // Capitalize the first character of each word String word = words[i]; if (!word.isEmpty()) { result.append(word.substring(0, 1).toUpperCase()); if (word.length() > 1) {
                    result.append(word.substring(1).toLowerCase());
                }
            }
        }        
        return result.toString();
    }
    public static void main(String[] args) {
        String fullName = "Edu CBA";
        System.out.println(convertStringToLowerCamelCase(fullName));
        String calculateSalary = "mARC MARON()";
        System.out.println(convertStringToLowerCamelCase(calculateSalary));
        String greetingMessage = "Hello edu CBA";
        System.out.println(convertStringToLowerCamelCase(greetingMessage));
    }
}

Output:

Explanation

StringConverter class:
- Contains the ConvertStringToLowerCamelCase method.
ConvertStringToLowerCamelCase method:
- Converts input string into lower-case.
- Splits the input string into spaces.
- Capitalize the first letter of each word (except the first word).
- Change the remaining letters to lowercase.
Converts the input strings to lowercase and prints the result.

2. Upper Camel Case

The upper camel case is also known as the title and Pascal cases. In this case, the first character of the identifier is in uppercase, and subsequent words also start with uppercase letters. Class and interface naming follows this convention.

For example, Employee, Printable, WebPageTitle, etc.

In other words, the first letter of each word should be capitalized, and the remaining letters should be lowercase.

This is a Java implementation of the above concept:

public class StringConverter {
    static String convertStringToUpperCamelCase(String inputString) {
        // Split the input string by spaces
        String[] words = inputString.split("\\s+");
        // Concatenate the words with proper capitalization
        StringBuilder result = new StringBuilder();
        for (String word : words) {
            // Capitalize the first character of each word
            if (!word.isEmpty()) {
                result.append(word.substring(0, 1).toUpperCase());
                if (word.length() > 1) {
                    result.append(word.substring(1).toLowerCase());
                }
            }
        }
        return result.toString();
    }
    public static void main(String[] args) {
        String fullName = "Edu CBA";
        System.out.println(convertStringToUpperCamelCase(fullName));
        String calculateSalary = "mARC MARON()";
        System.out.println(convertStringToUpperCamelCase(calculateSalary));
        String greetingMessage = "Hello edu CBA";
        System.out.println(convertStringToUpperCamelCase(greetingMessage));
    }
}

Output:

Explanation:

Convert input strings into upper camel case format.
The code splits the input string, treating each word as a separate entity.
It capitalizes the first character of each word.
It converts the remaining characters of each word to lowercase.

Rules of Camel Case

These are essential rules for the Camel Case.

The first letter of the first word in lower camel case should be lowercase. The first letter of the first word in upper camel case should be uppercase.

Lower camel case example: firstName
Upper camel case example: FirstName

Each subsequent word in the identifier should start with an uppercase letter.

Example: camelCaseIdentifier

There should not be any spaces in the name of the identifier.

You should maintain consistency throughout your codebase. It would help if you chose either lower camel or upper camel case to name variables, methods, classes, and interfaces.

It would help if you chose meaningful and descriptive names for your identifiers for readability and maintainability.

It would help if you did not change abbreviations. For example, you should name “XMLHttpRequest” instead of this “XmlHttpRequest”. Each programming language has its naming convention in the camel case.

Benefits of Using Camel Case

There are various benefits to using camel case. We have discussed some of them.

Readability:

Camel case improves readability and understanding for everyone.
Example: The variable numberOfWidgets is easier to read than numberofwidgets.

Easier Identification:

Enables easy identification and alteration of functions and variables.

Fewer Joins:

Reduces the number of instances where the second word is joined and capitalized.

Ease of Writing:

Camel case requires one less keystroke compared to alternatives.

Easier to Remember:

Many websites use CamelCase in their domain names to enhance readability and memorability.

Avoids Spaces and Errors in URLs:

Spaces in URLs are percent-encoded as “%20,” making the address longer and less human-readable.
Avoiding spaces in URLs mitigates this issue.

Accessibility with Screen Readers:

Screen readers may struggle to recognize individual words in long, lowercase hashtags.
Camel case improves accessibility for people who use screen readers.

Using Camel Case in Java Programming

There are some exceptions to naming in Java programming. We have these naming rules, with examples and exceptions below.

1. Naming Variables and Constants

You should use the Upper camel case for naming classes and Interfaces. In class names, every first letter of each word should be capitalised, and the remaining letters should be in lowercase. For example,

final int MAX_VALUE = 100;
final double PI = 3.14159;

Note that there is an exception for constants declared inside interfaces.

For variable naming in Java, you can use lower camel case. Names should be meaningful and consistent. For example,

// Good variable names
int numberOfStudents;
double averageScore;
String userName;
// Avoid single-letter names or abbreviations
int nStudents; // Avoid abbreviations
int x; // Unclear purpose, use meaningful names instead

2. Naming Classes and Interfaces

You should use the Upper camel case for naming classes and Interfaces. In class names, every word’s first letter should be capitalised, and the remaining letters should be in lowercase. For example,

public class MyClass {
    // Class members and methods
}

public interface MyInterface {
    // Interface members and methods
}

Therefore, you can easily distinguish classes and interfaces from variables and methods. Hence, more code readability and understandability.

3. Naming Methods and Functions

You should use lower camel case for naming methods and functions in Java. The first word starts with a lowercase letter and subsequent words begin with uppercase letters. For example,

public void myMethod() {
    // Method implementation
}
public int calculateSum(int num1, int num2) {
    // Method implementation
}

Therefore, you can easily distinguish variables and methods from classes and interfaces. Hence, more code readability and understandability.

Tools and IDE Support for Camel Case

There are various tools and IDE which support the camel case naming convention.

IIDE Support:

Integrated Development Environments (IDEs) such as IntelliJ IDEA, Eclipse, and NetBeans support camel case naming conventions.
These IDEs offer built-in features like auto-completion and code suggestion, which assist developers in adhering to camel case standards while coding.

Code Linters:

Tools like Checkstyle and SonarQube, including camel case, provide rulesets for checking naming conventions.
They help ensure consistency and adherence to coding standards throughout the development process.

Version Control Systems:

Version control systems like Git integrate pre-commit hooks, which can enforce camel case consistency among team members.
It helps maintain uniformity in naming conventions across the codebase, enhancing readability and maintainability.

Custom Scripts and Online Validators:

Developers can also utilize custom scripts and online validators to streamline maintaining code readability and enforcing camel case standards.

Common Mistakes to Avoid

These are some common mistakes to avoid in camel cases in Java.

1. Using the wrong case for the first letter

Camel case variable names should not contain underscores and spaces. For example, the following variable is misnamed:

int MyVariable = 10;

The correct way to name this variable would be:

int myVariable = 10;

2. Using underscores and spaces in variable names

Camel case variable names should not contain underscores and spaces. For example, the following variable is named incorrectly:

int my_variable = 10;

The correct way to name this variable would be:

int myVariable = 10;

3. Using abbreviations in variable names

Camel case variable names should be spelled out in full. For example, the following variable is named incorrectly:

int nStudents = 10;

The correct way to name this variable would be:

int numberOfStudents = 10;

4. Using reserved words in variable names

It would help to not use reserved words as variable and method names. Reserved words have special meanings in Java. For example, the following variable is named incorrectly:

int class = 10;

The word “class” is a reserved word in Java. So you cannot use it as a variable name. The correct way to name this variable would be:

int class = 10;

5. Inconsistent naming

It would help if you used either lower or upper case for naming conventions in a Java program, but not both.

Case Studies and Examples

A. Before and After: Refactoring Code for Camel Case

You should refactor your code to adhere to naming conventions in Java. For example, consider this Java program which does not follow camel case conventions.

Before Refactoring:

public class calculate_average {
    public static void main(String args[]) {
        int total_marks = 0;
        int number_of_students = 5;
        int[] student_marks = {90, 85, 78, 92, 88};
        for (int i = 0; i < number_of_students; i++) {
            total_marks += student_marks[i];
        }
        double average_marks = (double) total_marks / number_of_students;
        System.out.println("Average Marks: " + average_marks);
    }
}

Now, you should refactor the code for the camel case. You need to rename variables, methods, classes, and other identifiers to follow this convention.

After Refactoring:

public class CalculateAverage {
    public static void main(String[] args) {
        int totalMarks = 0;
        int numberOfStudents = 5;
        int[] studentMarks = {90, 85, 78, 92, 88};
        for (int i = 0; i < numberOfStudents; i++) {
            totalMarks += studentMarks[i];
        }
        double averageMarks = (double) totalMarks / numberOfStudents;
        System.out.println("Average Marks: " + averageMarks);
    }
}

In this code, we have followed lower camel case for variables and upper camel case for class names.

Output:

B. Real World Examples

These are real world examples of camel case naming convention.

1. Computer programming

Some companies and technologies use camel case. It is used to create new words out of existing ones to register as trademarks. For example, Java uses a camel case to practice writing the names of methods, variables, classes, packages, and constants.

2. Online usernames

People sometimes use camel case for online usernames, like JohnSmith.

3. Domain names

Camel case is used for multi-word domain names more legible. For example, promoting EasyWidgetCompany.com.

4. In programming and scripting languages

CSS selectors, JSON data, SQL connections, JavaScript variables, and HTML tags.

These words are all the result of fusing several words together to form a single word. This makes the code simpler to read and comprehend.

5. Product and company names

Many well-known technology companies and their products use camel case in their naming conventions, such as YouTube, iPhone, eBay, AirDrop, DisplayPort, OneDrive, PlayStation, TechTarget, ComputerHope, FedEx, and WordPerfect.

Conclusion

Camel Case is a naming convention used in Java and other programming languages. Lower camel case is used for naming variables and methods in Java. Java convention dictates using upper camel case for naming classes and interfaces. The word’s first letter should be in lowercase camel case. Meanwhile, the word’s first letter should be in upper and upper camel cases. Only the first letters of each other word should be in capital letters; all other letters should be in lowercase. There should not be any spaces in the name of the identifier. In the real world, there are various uses of camel case, like in trademark, domain name styling, Product and company names, usernames, etc. The camel case naming convention provides more readability and clarity.

Frequently Asked Questions (FAQs)

Q1: Can camel case be used for naming method parameters?

Answer: Yes, method parameters can be used in the camel case. It would help if you utilized the same conventions as variable names.

Q2: Is camel case applicable to naming package structures in Java?

Answer: Yes. Camel case can be used to name package structures. Note that it is common to use lowercase letters for package names. However, you should also follow the camel case naming convention for package structures.

Q3: Is there a preferred naming convention for enum constants in the camel case?

Answer: Yes. The enum constants should use the upper camel case convention for consistency and readability.

Quiz Result
Total Questions	Correct Answers	Wrong Answers	Percentage

Introduction to Camel case in Java

Table of Contents

Key takeaways

Understanding Camel Case Conventions

1. Lower Camel Case

2. Upper Camel Case

Rules of Camel Case

Benefits of Using Camel Case

Using Camel Case in Java Programming

1. Naming Variables and Constants

2. Naming Classes and Interfaces

3. Naming Methods and Functions

Tools and IDE Support for Camel Case

Common Mistakes to Avoid

Case Studies and Examples

A. Before and After: Refactoring Code for Camel Case

B. Real World Examples

Conclusion

Frequently Asked Questions (FAQs)

Recommended Articles

Follow us!

APPS

Blog

Courses

Email