What Is Code Smell? 7 Examples Every New Developer Should Know

Is Your Code “Smelly”? Here’s Why It Matters

Ever written a piece of code that worked perfectly fine… but something about it felt off? Maybe it was harder to read than you’d like. Or maybe you made a small change and suddenly things started breaking in unexpected ways.

That uneasy feeling is often a sign of a code smell.

A code smell doesn’t mean your code is broken. It means there’s a deeper design issue lurking beneath the surface — the kind that can lead to bugs, technical debt, and endless headaches for future you (or your team).

Here’s why new developers should care:

• Cleaner code is easier to read, debug, and maintain.
• Avoiding code smells early prevents small problems from snowballing into big ones.
• Knowing common code smells helps you write professional-grade code from day one.

The good news? You don’t need years of experience to start spotting them.

In this post, you’ll learn:

✅ What code smell really means (with simple, beginner-friendly language)
✅ 7 common examples every new developer should watch out for
✅ Quick tips on how to avoid these bad coding practices

By the end, you’ll have a sharper eye for messy code — and know exactly how to start cleaning it up.

What Is Code Smell? (And Why It’s Not About Your Code Literally Smelling)

A code smell is a sign that something might be wrong with your code’s design. It’s not an outright error or bug — your program still runs and does what it’s supposed to. But underneath, there’s a hint of trouble that could grow into bigger issues later.

Think of it like this:

Your car makes a weird clicking sound when you turn the wheel. It still drives fine, but you know you shouldn’t ignore it. That sound is a warning — a “smell” — that something needs attention before it gets worse.

In programming, a code smell works the same way. It’s a surface indication of deeper problems like poor structure, duplication, or overcomplication.

Here’s what a code smell is NOT:

• 🚫 A syntax error
• 🚫 A bug that stops your program from running
• 🚫 Something your IDE will always warn you about

Instead, it’s a red flag for things like:

• Difficult-to-read code
• Functions or classes doing too much
• Fragile code that breaks easily when modified

Why does this matter? Because code with smells often leads to technical debt, making it harder for you (or your teammates) to maintain, extend, or debug later.

The key takeaway:
Just like strange car noises, code smells don’t fix themselves. Spotting them early helps you write cleaner, healthier code.

Why Should New Developers Care About Code Smells?

As a new developer, it’s easy to think, “If my code works, isn’t that enough?” But here’s the thing — working code isn’t always good code.

Ignoring code smells early on can lead to bigger problems as your projects grow. Here’s why you should start caring about them from day one:

Cleaner Code Is Easier to Maintain

Code without smells is easier to read, understand, and modify. When you or someone else revisits it months later, you won’t have to waste time figuring out what’s going on.

Example:
Imagine a function with 200+ lines doing 10 different things. It works… but good luck trying to update just one part without breaking something else.

You Avoid Building Technical Debt

Technical debt is like taking shortcuts in your code today that you’ll have to “pay back” later with extra work.
By spotting code smells early, you prevent this debt from piling up.

It Makes Teamwork Easier

In collaborative projects, clean code is a lifesaver. Code full of smells is harder for others to read, debug, or extend — and that can lead to frustrated teammates.

Ignoring Code Smells Leads To…

• Harder debugging sessions
• Fragile systems that break easily when changed
• Unhappy teams who have to clean up messy code later

The good news? You don’t need to become a senior developer to start spotting these issues. You just need to know what to look for.

So what are some common code smells you should watch out for? Let’s break down seven of them that every new developer is likely to encounter.

7 Common Code Smell Examples Every Developer Should Know

Now that you know what a code smell is and why it matters, let’s look at some real examples.

These are seven of the most common code smells that every new developer is likely to encounter. Each one comes with a simple explanation and a quick tip on how to fix or avoid it.

You don’t need to memorize them all right away. Instead, use this list as a reference to help you recognize bad coding patterns in your own projects.

As you read through, ask yourself:
Have I written code like this before?
What could I do differently next time?

Let’s dive in.

1. Long Method

A long method is a function that tries to do too many things at once. It keeps growing as you add more logic, until it becomes hundreds of lines long.

This makes the code:

• Hard to read
• Difficult to understand at a glance
• Almost impossible to test properly

Why it’s a code smell:
It violates the Single Responsibility Principle — a function should do one thing and do it well.

Example:

def process_order(order):
    # validate order
    # calculate totals
    # apply discounts
    # update inventory
    # send confirmation email
    # log order details

This method handles too many tasks instead of focusing on one.

How to fix it:
Break the long method into smaller, focused functions:

def process_order(order):
    validate(order)
    total = calculate_total(order)
    update_inventory(order)
    send_confirmation(order)

Each function now has a clear, single responsibility.

2. Large Class (God Object)

A large class, often called a “God Object,” is a class that tries to control too much. It knows about everything in the system and manages multiple responsibilities.

This leads to:

• Complex, hard-to-maintain code
• Poor reusability (you can’t use parts of the class elsewhere)
• A higher chance of bugs when making changes

Why it’s bad:
The class becomes a bottleneck — touching it can break unrelated parts of your code.

Example:

public class OrderManager {
    // handles customer data
    // processes payments
    // updates inventory
    // sends notifications
}

This class is doing way too much.

How to fix it:
Split the responsibilities into smaller, cohesive classes:

• CustomerManager for customer data
• PaymentProcessor for payments
• InventoryUpdater for stock management
• NotificationService for sending updates

This keeps your code modular and easier to maintain.

3. Duplicated Code

Duplicated code happens when the same logic or block of code appears in multiple places. At first, it might seem harmless — copy-pasting feels faster. But over time, it creates a maintenance nightmare.

Why it’s bad:

• If you need to make a change, you must update every instance of the duplicated code.
• Missing even one spot can cause bugs or inconsistencies.

Example:

# In multiple parts of your app
if user.is_logged_in:
    print("Welcome, " + user.name)
    show_dashboard(user)
else:
    print("Please log in first")

If the welcome logic changes, you now have to edit it everywhere it appears.

How to fix it:
Extract the common code into a single function:

def greet_user(user):
    if user.is_logged_in:
        print("Welcome, " + user.name)
        show_dashboard(user)
    else:
        print("Please log in first")

Now you only maintain it in one place.

4. Feature Envy

Feature envy happens when one class constantly accesses the data or methods of another class. It’s like saying, “I wish I were part of that class instead.”

This is a red flag because it shows that the functionality probably belongs in the other class.

Why it’s a code smell:
It leads to tight coupling between classes, making your code harder to maintain or extend.

Example:

// OrderProcessor keeps accessing Order’s data
double total = order.getSubtotal() + order.getTax() - order.getDiscount();

Here, OrderProcessor relies too heavily on Order’s internals.

How to fix it:
Move the calculation logic into the Order class:

// Inside Order class
public double calculateTotal() {
    return subtotal + tax - discount;
}

Now OrderProcessor can simply call order.calculateTotal(), keeping responsibilities where they belong.

5. Primitive Obsession

Primitive obsession happens when you overuse basic data types like strings, integers, or booleans instead of creating meaningful objects.

This can make your code harder to manage, especially as your project grows.

Why it’s bad:

• It scatters related logic across your codebase.
• Any change to how a “primitive” is handled means updating multiple places.
• It reduces code readability and increases the chance of errors.

Example:

# Using primitives to represent a phone number
def send_sms(country_code, area_code, number, message):
    pass

Here, every time you deal with a phone number, you’re passing around multiple primitives.

How to fix it:
Wrap the primitives into a meaningful object:

class PhoneNumber:
    def __init__(self, country_code, area_code, number):
        self.country_code = country_code
        self.area_code = area_code
        self.number = number

def send_sms(phone_number, message):
    pass

Now all phone number logic lives in one place, making it easier to extend or validate later.

6. Long Parameter List

A long parameter list is when a function takes in too many arguments.

This often signals that your function is trying to do too much or that related data isn’t properly grouped.

Why it’s bad:

• Harder to read and understand what the function needs
• Increases the chance of passing arguments in the wrong order
• Makes code brittle when parameters change

Example:

// A function with too many parameters
createUser(String firstName, String lastName, String email, String phone, String address, String city, String zip)

This is hard to read, and every call to createUser requires remembering the correct order.

How to fix it:
Group related parameters into objects:

class UserProfile {
    String firstName;
    String lastName;
    String email;
    String phone;
    Address address;
}

createUser(UserProfile profile)

Now the function is cleaner and more maintainable.

7. Comments Instead of Clean Code

Sometimes you’ll see code with lots of comments explaining what the code does. While comments can help, relying on them too much is actually a code smell.

Why it’s a smell:
Good code should be self-explanatory. If you need tons of comments to explain what your code does, it probably means your code is confusing or poorly named.

Example:

# Increment counter by 1
counter = counter + 1

This comment is unnecessary — the code is clear on its own.

How to fix it:

• Use meaningful variable and function names so the code tells its own story.
• Refactor complex logic into smaller, well-named functions.
• Reserve comments for explaining why something is done, not what is done.

---

How to Detect Code Smells Early

Spotting code smells early can save you hours of headaches later. Here are some practical ways to catch them as you code:

1. Use Static Analysis Tools

Tools like SonarQube, ESLint, or CodeClimate scan your code for common smells and potential issues automatically. They provide actionable feedback before bugs sneak in.

2. Participate in Peer Code Reviews

Having teammates review your code helps catch smells you might miss. Fresh eyes often spot unclear or messy code quickly.

3. Follow Clean Code Principles

Books like Robert C. Martin’s Clean Code offer timeless advice on writing readable, maintainable code. Adopting these habits helps you avoid smells naturally.

4. Develop a Habit of Spotting Smells

Make it part of your daily workflow to pause and ask:

• Is this method doing too much?
• Could this be broken into smaller parts?
• Are variable names clear and meaningful?

Over time, this mindset becomes second nature.

Following clean code principles, as described by Robert C. Martin (Uncle Bob), can help you avoid many common smells (cleancoders.com).

Final Thoughts

Avoiding code smells isn’t just about making your code look neat — it’s about writing software that’s easier to maintain, less buggy, and ready to grow with your projects.

As a new developer, learning to spot these warning signs early is one of the best investments you can make in your coding career. It’s the first step toward writing professional-grade code that you and your teammates will thank you for.

Remember: every seasoned developer started where you are now — noticing these smells and learning how to fix them takes practice.

---

What About You?

Have you ever spotted a code smell in your projects? How did you handle it?

Share your stories or questions in the comments below — your experience might help other developers on the same journey.

And if you want more practical tips on writing clean, maintainable code and growing as a developer, don’t forget to subscribe to StayAhead.tech!