Introduction: What Is Clean Code?

Clean code is a concept every software engineer has encountered, yet many struggle to define precisely. While most developers agree that clean code is important, understanding what it truly means requires more than just following rules—it requires intent.

Michael Feathers captures this idea perfectly:

“Clean code always looks like it was written by someone who cares.”

Clean code reflects clarity, intention, and respect for the next person who reads it—often your future self.

At its core, clean code can be summarized by a few fundamental principles:

• Use proper and meaningful names
• Keep methods short
• Keep classes small and focused
• Avoid code duplication (DRY principle)
• Minimize side effects

This article focuses primarily on naming and code size, as these two factors have the most immediate and visible impact on readability and long-term maintainability.

The Importance of Proper Naming

Naming is one of the hardest problems in software development. Developers often prefer short names because they are faster to type, but this convenience comes at the cost of clarity.

Code is read far more often than it is written. Poor naming forces readers to mentally translate intent, increasing cognitive load and the likelihood of mistakes.

Consider this example:

int d;

What does d represent? Days? Distance? Discount?

Now compare it with:

int daysUntilExpiration;

The intent is immediately clear.

Good Naming Improves Understanding

Bad naming often relies on abbreviations:

BigDecimal amt;
boolean flg;
User usr;

Clear naming removes ambiguity:

BigDecimal transactionAmount;
boolean isVerified;
User authenticatedUser;

A variable should describe exactly what it represents. Finding the right name often takes several attempts—and that is completely normal. Modern IDEs make renaming safe and easy, so naming should evolve as your understanding improves.

Naming Beyond Variables

Proper naming applies equally to methods and classes:

• Methods starting with get should return a value
• Boolean methods should read like questions (isActive, hasPermission)
• Generic class names like Manager, Helper, or Utils should be avoided

Clear naming communicates intent and significantly reduces the need for comments.

Keeping Classes and Methods Short

Small, Focused Classes

A widely accepted clean code principle is that a class should do one thing.

In Java, this often limits classes to around 200 lines or fewer. When a class grows too large, it becomes harder to name—and that is usually a sign that it does too much.

A common red flag is feeling the urge to write unit tests that directly call private methods. This usually indicates that multiple responsibilities are hidden inside a single class and should be extracted.

Short, Readable Methods

Short methods improve readability by operating at a single level of abstraction.

Consider this example:

public void processOrder(Order order) {
    validateOrder(order);
    calculateTotal(order);
    applyDiscounts(order);
    saveOrder(order);
    sendConfirmationEmail(order);
}

Each method name clearly explains what happens, without exposing how. This makes the code easier to read, test, and modify.

Long methods that mix validation, calculations, persistence, and formatting tend to hide intent and make future changes risky.

Real-World Example: Misleading Variable Naming

Consider the following class:

public class PaymentResult {

    private BigDecimal amount;

    public BigDecimal getAmount() {
        return amount;
    }
}

At first glance, this looks reasonable. But what does amount represent?

• Requested amount?
• Paid amount?
• Remaining balance?

The name lacks context.

A clearer version might look like this:

public class PaymentResult {

    private BigDecimal processedPaymentAmount;

    public BigDecimal getProcessedPaymentAmount() {
        return processedPaymentAmount;
    }
}

Although the name is longer, it is also precise. In clean code, clarity always takes precedence over brevity.

When Class Names No Longer Match Their Responsibilities

As software evolves, classes often accumulate additional responsibilities. Over time, the class name may no longer reflect what the class actually does.

For example, a class named InvoiceGenerator that also sends emails and updates account balances violates the Single Responsibility Principle.

Renaming it to something generic like InvoiceManager only hides the problem. The correct solution is refactoring—splitting responsibilities into smaller, well-named classes.

Clean code requires continuous design. Without regular refactoring, even well-written code will degrade.

The Role of Comments in Clean Code

Contrary to popular belief, comments do not make code cleaner.

Well-written code should explain itself through clear naming and structure. Comments often become outdated, while code always reflects the current truth.

Instead of this:

// check if user is active 
if (user.getStatus() == 1) {

Prefer this:

if (user.isActive()) {

Comments are valuable only when they explain why something is done a certain way—especially when alternative solutions were considered and rejected.

Commented-out code should be removed entirely. Version control systems preserve history far better than commented blocks ever could.

Writing Methods That Clearly Express Intent

Method names should clearly describe what condition they evaluate and when they return true.

Consider this method:

boolean checkBalance(BigDecimal oldValue, BigDecimal newValue) 

The name is vague. What does “check” mean? When does it return true?

A clearer version would be:

boolean isBalanceUnchanged(
   BigDecimal previousBalance,
   BigDecimal currentBalance
)

This reads naturally in an if statement and leaves no ambiguity.

Clear method names reduce cognitive load and eliminate the need for explanatory comments.

Additional Clean Code Principles

Clean code goes beyond naming and size. Supporting principles include:

• Single Responsibility Principle (SRP): Each class or method should have one reason to change
• Consistent Formatting: Uniform style improves readability and reduces visual noise
• Avoid Hidden Side Effects: Methods should do exactly what their name suggests
• Refactor Continuously: Clean code is maintained through constant improvement

Conclusion

Clean code is not written in a single pass. It is refined through continuous care and attention.

Every time you touch existing code, you have an opportunity to improve it—by choosing clearer names, extracting smaller methods, or simplifying responsibilities.

If you consistently leave code better than you found it, clean code becomes a natural outcome rather than a forced discipline.