What Is Clean Coding in Java?


No matter what coding language you choose, the capability to write clean code is essential, and it is notably vital if you work with Java.  

Java is the most widely used programming language, and its codebases have a long shelf life. Many Java programs are upgraded and managed by users. Thus, you must know how to write clean code in Java for versatility and extended usability. 

At the same time, writing clean code takes work. Compared to many other popular programming languages — such as C and Python — Java is more verbose. You have to write more Java code to implement the functionality, and the more code you write, the harder it becomes to keep it lean, mean, and clean. 

In this article, we will go through clean coding principles, learn why we need clean code, and provide tips for clean coding in Java. 

What Is Clean Code?  

Clean coding is the practice of developing code that is easily readable, tested, and less likely to contain mistakes.  

Clean code is easy to read and understand. It is well-organized and consistent, according to the Java programming language’s standard norms. 

Most critically, clean code is devoid of mistakes and flaws. To write clean code, you must be familiar with the Java language and its syntax. A syntax includes the principles governing how any Java program is created and understood. It would also be advantageous if you had a strong understanding of object-oriented programming concepts. 

Why Do We Need Clean Code? 

There are various reasons why we need clean code, explained below are the most critical ones:  

1. Best Practices 

Software best practices such as unit testing, TDD, CI, and others have had rapid acceptance in recent years. These methods raise the quality and maintainability of the code. When it’s time to rewrite or test code, applying clean coding principles is a key skill that pays off well. It’s easier to read and test clean code. 

2. Logic Behind the Code 

If someone disputes the quality of your code, you ought to be able to respond with a reasonable justification. There is an opportunity for improvement if you have never logically evaluated the quality of your coding style. Clean coders have specified tasks, patterns, and approaches for keeping the code clean. 

3. Maintenance 

Reading a codebase is more difficult than writing it. For this reason, developers would rather write new code than study and comprehend old code. Compared to the alternative strategy, which involves writing code as quickly as possible without taking readability into account, writing readable code is significantly more economical..  

4. Easy to Test 

Automated testing of the code is made possible for clean code. Test-driven development, which automates testing, is the most efficient method for enhancing the productivity of the team, reducing the number of software issues, and improving the quality of the code. The sum of these factors greatly increases the product’s overall ROI. 

Characteristics of Clean Code in Java 

Key characteristics of clean code are as follows: 

  • Scalability Is Must for Code 

Code that can scale with the needs of your business is a key feature of effective programming. Scalability is primarily concerned with code efficiency. Scalable programming does not require constant redesigns to sustain speed and manage variable workloads. 

  • Code Must Be Valid 

A testable code is an excellent code as it is always ready for release. Last-minute adjustments are unavoidable in software development. It is difficult to implement new improvements if the code cannot be swiftly and dynamically regression-tested. 

If the code is competent enough, you do not have to test the entire product to make minor changes. You can test updated elements in seclusion while remaining confident in the overall flow. 

  • Code Performs the Intended Function 

Every software component that is ever implemented serves a purpose. A code that adheres to its requirements is simple to understand for those who are familiar with the functionality. As a result, fulfilling the functional requirement is a vital characteristic of excellent code. 

Tips for Clean Coding in Java 

Here are a few ways to verify the code comes out clean: 

1. Project Structure  

It refers to how you organize your project components, such as source files, data, settings, tests, and more. 

Maintaining an effective project structure is critical for reducing file search time. There is no requirement in Java that instructs you to follow a structure for your project, but it does not imply you should not have. Having the project structure is an ideal approach. 

2. Naming Convention  

Using a naming convention is a terrific method to start, as it keeps things orderly and allows you to understand your management. 

A naming convention is when you refer to your variables by names that follow a set of conventions. It can get messy, and not everyone can decide which option is best. So, to keep things simple, it can be as easy as instantiating variable names with their data type, as in 

int MyfirstInteger = 12;  

float MyfirstFloat = 12.5; 

3. Source File Structure  

A source file contains a variety of items. While the Java compiler mandates some structure, the rest is dynamic. However, following a precise sequence in which to insert items in a source file can considerably increase code readability. 

Let’s have a glance at how a typical element arrangement in a source file should appear: 

  • Package statement 
  • Import statements[Text Wrapping Break] 
  • Static imports 
  • Non-static imports 
  • One top-level class[Text Wrapping Break] 
  • Class variables 
  • Instance variables 
  • Constructors 
  • Methods 

Methods can also be classified depending on their usefulness or scope. There is no one suitable convention, and the principle should be determined once and then consistently followed. 

4. Whitespaces and Indentation 

Using whitespace can be extremely effective and generally has no drawbacks. In Java, where the file size of the source code is crucial, you may want to keep your files compact, and whitespace can add a few unnecessary kilobytes. Keep as much whitespace as possible throughout development to keep the code legible. Then, right before you launch it, use any program that scans through code and removes all the whitespace. 

5. Method Parameters  

We construct methods with parameters, but occasionally we add so many parameters to a single method that it creates confusion. The principle here is simple: if feasible, stop adding more than three arguments, as this can cause extra complications for other developers or programmers working with that code. If possible, you can also consider refactoring, as seen in the example below: 

Refactoring is a programming method for rearranging existing code without changing its exterior behavior. 


// Before 

private void studentDetails(String firstname, String age, String marks, String fees, String class). 

// After 

private void studentDetails(String firstname, Details studentDetails). 

6. Hardcoding  

Hardcoding data in code can usually result in a plethora of unintended consequences. For example, it may result in duplication, making modification more difficult. If the values must be dynamic, it can frequently lead to unwanted behavior. Hard-coded values can usually be refactored in one of the following ways: 

  • Consider replacing them with Java-defined constants. 
  • Alternately, use constants declared at the class level or in a separate class file. 
  • If practicable, substitute with values from the configuration or environment. 

For example, 

private double SchoolClosingDay = 1; 


// This can be refactored to use a Java constant. 


private int SchoolClosingDay= Dayofweek.SUNDAY.getValue() 

7. Code Comments  

Putting comments in your code can be extremely useful—it can swiftly demonstrate what a convoluted function performs or clarify the sequence of specific actions. Comments can assist others in comprehending what problems you were striving to tackle with your code, which can assist them in developing more effective solutions. Keep in mind that excessive commenting can occasionally have a negative impact by resulting in a messier code. 

8. Logging  

One of the most crucial aspects of clean code is logging. A well-logged code is simple to troubleshoot and can save a developer’s time. Excessive logging should always be avoided as it may lead to lower performance. 

 9. DRY and KISS principle  

DRY is an acronym for Don’t Repeat Yourself. It stresses not duplicating code. Simply expressed, the major goal of this approach is to make the code reusable. It states that every element of information must have a definitive presentation within a system and must signify the idea/functionality it has conveyed. 

The abbreviation KISS stands for Keep It Simple, Stupid. As the acronym implies, this concept emphasizes that the code should be kept as basic as feasible. It emphasizes that we can’t utilize something correctly if we don’t understand it. And that the broadest possible audience must understand the product if it is to acquire maximum market share. 

10. TDD Method  

TDD is an abbreviation for Test Driven Development. This programming strategy requires you to create code only when an automated test fails. JUnit and TestNG are two frameworks for writing automated unit tests in Java. 

The advantages of such a technique are enormous. This results in software that performs as planned. We always start with testing and then add functioning code in small bits. Furthermore, we only add code if the new or any of the existing tests fail. As a result, it also contributes to reusability. 

11. SOLID 

SOLID is an abbreviation for the five principles it establishes for developing intelligible and maintainable software: 

  • Single Responsibility Principle 

The Single Responsibility Principle asserts that any interface, class, or function we write should be precise with a single responsibility. 

  • Open/Closed Principle 

The Open/Closed Principle states that our code should preferably be open to any type of extension but closed to any alteration. 

  • Liskov Substitution Principle 

Principle asserts that the objects of a superclass should be interchangeable with the objects of its subclasses without breaking the application. 

  • Interface Segregation Principle 

It seeks to decrease the number of needed modifications and side effects from code by breaking or dividing the software into several distinct pieces or interfaces. 

  • Dependency Inversion Principle 

The Dependency Inversion Principle states that classes should only rely on abstractions rather than implementations. 


Remember that an alternative to clean code is not incorrect code. It is not necessarily bad if a section of your application code does not check some of the parameters mentioned above. 

Depending on the conditions, tools available, and project timeframes, developers can choose to write code that is difficult to update afterward. You can select how to execute your needs as long as you grasp the clean code principles in Java and are familiar with the features of clean code. For more information and certification courses on cutting-edge technologies, we suggest you explore UNext

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