Here are 10 coding best practices that have helped me write better Java code— and how you can apply them in your projects.
1. Avoid Null References Using Optional
Problem: NullPointerException is one of the most common runtime errors in Java.
How I Fixed It: Instead of returning null, I started using Optional<T>.
CopyOptional<String> result = findUserById(123);
result.ifPresent(user -> System.out.println(user.getName()));
✅ Benefit: Eliminates unnecessary null checks and makes the code more robust.
2. Use StringBuilder Instead of String Concatenation
Problem: Using + to concatenate strings inside loops led to performance issues.
How I Fixed It: I switched to StringBuilder for better efficiency.
CopyStringBuilder sb = new StringBuilder();
for (int i = 0; i < 1000; i++) {
sb.append("Line ").append(i).append("\n");
}
String result = sb.toString();
✅ Benefit: Reduced memory usage and improved performance, especially in large loops.
3. Use Proper Exception Handling
Problem: I used to catch generic exceptions, making debugging harder.
How I Fixed It: Now, I catch specific exceptions and log meaningful messages.
Copytry {
Files.readAllBytes(Paths.get("file.txt"));
} catch (IOException e) {
System.err.println("Failed to read file: " + e.getMessage());
}
✅ Benefit: Easier debugging and better understanding of failure points.
4. Favor Composition Over Inheritance
Problem: Deep inheritance hierarchies made my code difficult to maintain.
How I Fixed It: I started favoring composition over inheritance.
Copyclass Engine {
void start() { System.out.println("Engine started"); }
}
class Car {
private final Engine engine = new Engine();
void drive() { engine.start(); System.out.println("Car is moving"); }
}
✅ Benefit: Improved flexibility, maintainability, and reduced tight coupling.
5. Use Streams for Clean Code
Problem: Writing multiple loops made my code verbose and hard to read.
How I Fixed It: I replaced loops with Java Streams.
CopyList<String> names = users.stream()
.filter(user -> user.getAge() > 18)
.map(User::getName)
.collect(Collectors.toList());
✅ Benefit: More readable and declarative code.
6. Write Unit Tests for Every Feature
Problem: Bugs slipped into production because I didn’t write tests consistently.
How I Fixed It: I adopted TDD (Test-Driven Development) and wrote tests before writing business logic.
Copy@Test
void testAddition() {
assertEquals(5, Calculator.add(2, 3));
}
✅ Benefit: Caught bugs early and improved code reliability.
7. Use Dependency Injection Instead of Hardcoded Dependencies
Problem: My code was tightly coupled, making it hard to modify or test.
How I Fixed It: I started using Spring Dependency Injection.
Copy@Component
class NotificationService {
void send(String message) { System.out.println("Sending: " + message); }
}
@Component
class UserService {
private final NotificationService notificationService;
@Autowired
UserService(NotificationService notificationService) {
this.notificationService = notificationService;
}
}
✅ Benefit: More flexible and testable code.
8. Optimize Database Queries to Avoid Performance Bottlenecks
Problem: My application slowed down due to inefficient queries.
How I Fixed It: I used batch processing, indexing, and optimized queries.
Copy@Query("SELECT u FROM User u WHERE u.status = :status")
List<User> findActiveUsers(@Param("status") String status);
✅ Benefit: Faster database interactions and reduced load time.
9. Follow Proper Naming Conventions
Problem: My old variable names were vague (x, temp, obj).
How I Fixed It: I switched to self-explanatory naming.
Copyint maxUsersPerPage = 50; // Instead of "x"
String customerFullName = "John Doe"; // Instead of "name"
✅ Benefit: Improved code readability and maintainability.
10. Use Design Patterns for Scalable Code
Problem: My codebase became unmanageable as my project grew.
How I Fixed It: I implemented Singleton, Factory, and Strategy patterns to organize code better.
Copypublic class DatabaseConnection {
private static final DatabaseConnection INSTANCE = new DatabaseConnection();
private DatabaseConnection() {}
public static DatabaseConnection getInstance() { return INSTANCE; }
}
✅ Benefit: Better code structure and easier scalability.
12 Resources and Coding Books to Learn Idioms and Best Practices
If you are wondering where you can learn these coding idioms and best practices, then let me tell you that books and online courses are some of the best ways to learn these coding idioms and other best practices.
- Clean Code — A must-read for writing maintainable, efficient, and readable code, with practical principles for software craftsmanship.
Clean Code: A Handbook of Agile Software Craftsmanship
Even bad code can function. But if code isn’t clean, it can bring a development organization to its knees. Every year…
- Code Complete — A comprehensive guide to software construction, covering coding best practices, design principles, and debugging techniques.
Code Complete: A Practical Handbook of Software Construction, Second Edition
Code Complete: A Practical Handbook of Software Construction, Second Edition [McConnell, Steve] on Amazon.com. *FREE*…
- Programming Pearls — A collection of classic programming insights, covering problem-solving, algorithm design, and coding efficiency. Link
Programming Pearls
Programming Pearls [Bentley, Jon] on Amazon.com. *FREE* shipping on qualifying offers. Programming Pearls
- Refactoring: Improving the Design of Existing Code (2nd Edition) — A practical guide to improving code structure while preserving functionality.
Refactoring: Improving the Design of Existing Code (2nd Edition) (Addison-Wesley Signature Series…
For more than twenty years, experienced programmers worldwide have relied on Martin Fowler’s to improve the design of…
- More Programming Pearls — A continuation of Programming Pearls, with additional problem-solving techniques and algorithmic insights.
More Programming Pearls: Confessions of a Coder: Confessions of a Coder
What do topics ranging from organic chemistry to Napoleon’s campaigns have to do with computer programming? This…
- Hacker’s Delight (2nd Edition) — A deep dive into bit manipulation, low-level programming tricks, and performance optimizations. Link
Hacker’s Delight
Hacker’s Delight: 9780321842688: Computer Science Books @ Amazon.com
- The Art of Computer Programming— Donald Knuth’s legendary multi-volume series on algorithms, data structures, and the mathematical foundations of programming.
The Art of Computer Programming, Volumes 1-4A Boxed Set
The Art of Computer Programming, Volumes 1-4A Boxed Set: 9780321751041: Computer Science Books @ Amazon.com
- Leading Lean Software Development: Results Are Not the Point — A practical take on applying lean principles to software development for efficiency and quality.
Leading Lean Software Development: Results Are Not the Point
Building on their breakthrough bestsellers and , Mary and Tom Poppendieck’s latest book shows software leaders and team…
- Working Effectively with Legacy Code — Essential strategies for refactoring and maintaining legacy codebases without breaking functionality.
Working Effectively with Legacy Code
Working Effectively with Legacy Code [Feathers, Michael] on Amazon.com. *FREE* shipping on qualifying offers. Working…
- Refactoring to Patterns — Combines refactoring techniques with design patterns to improve software structure.
Refactoring to Patterns
In 1994, “Design Patterns” changed the landscape of object-oriented development by introducing classic solutions to…
- Beautiful Code — A collection of essays by expert programmers, showcasing elegant and efficient coding techniques.
Beautiful Code: Leading Programmers Explain How They Think
How do the experts solve difficult problems in software development? In this unique and insightful book, leading…
- The Art of Readable Code — Practical tips on writing clear, simple, and readable code that others can easily understand.
The Art of Readable Code: Simple and Practical Techniques for Writing Better Code
The Art of Readable Code: Simple and Practical Techniques for Writing Better Code [Boswell, Dustin, Foucher, Trevor] on…
- Object-Oriented Analysis and Design — A foundational book by Grady Booch on designing scalable, object-oriented systems.
Object-Oriented Analysis and Design with Applications
Section I: Concepts Chapter 1: Complexity Chapter 2: The Object Model Chapter 3: Classes and Objects Chapter 4…
- The Effective Engineer — Focuses on maximizing impact as a software engineer by prioritizing high-leverage activities.
The Effective Engineer: How to Leverage Your Efforts In Software Engineering to Make a…
The Effective Engineer: How to Leverage Your Efforts In Software Engineering to Make a Disproportionate and Meaningful…
Conclusion
That’s all, friends. These 10 Java coding best practices and idioms helped me write cleaner, faster, and more maintainable code. If you’re struggling with messy or inefficient Java code, start applying these techniques in your projects.
Which of these best practices have you already adopted? Let me know in the comments!