Java Best Practices: Writing clean and efficient code

Millions of developers worldwide utilize Java, one of the most widely used programming languages. Developing readable, maintainable Java code is essential to creating effective and high-quality applications.

In this thorough tutorial, we will look at a few best practices that Java developers can adhere to to write better code. We will go over various subjects, including writing styles, formatting, naming standards, concurrency, collections, and streams. Acquiring knowledge of these optimal techniques can help you build more robust Java code and become more productive.

So, let’s dive right in!

Code Formatting

Consistency in code layout is crucial to developing clean, understandable Java code. Here are some guidelines for writing best practices.

• Put four spaces between each code block to ensure correct indentation, and stay away from tabs. Code flow and hierarchy are more visible when indentation is done correctly.
• After commas, colons, and other punctuation, insert whitespace to surround operators. Reading code is made easier by whitespace.
• 100–120 characters are the maximum character length allowed. It’s challenging to read long lines.
• Ensure that you always use parenthesis. Put the opening and closing brackets for the Java parenthesis on separate lines, with the opening bracket on the same line as the construct. Remain dependable!

Following standard code formatting guidelines ensures uniformity across your codebase so that anyone can easily navigate through it. Most IDEs allow configuring formatters – make most of them!

Naming Conventions

Using proper naming conventions is one of the most crucial Java best practices. Names should be descriptive, concise, and consistent across the codebase.

Here are some Java naming convention best practices:

• Class names: PascalCase (e.g. EmployeeService)
• Interface names: PascalCase prefixed with capital I (e.g. IEmployeeService)
• Method names: camelCase (e.g. getEmployee())
• Variable names: camelCase
• Constants: UPPER_SNAKE_CASE (e.g. MAX_EMPLOYEES)

Additionally, avoid using one or two letter names that don’t indicate anything. Also,, avoid names that differ only by capitalization (foo and Foo), as it gets extremely confusing.

Follow language best practices for abbreviations and acronyms usage. For example, use HttpURLConnection instead of HTTPURLConnection.

Writing Methods

Here are some best practices you should follow while writing methods in Java:

• Keep methods small: large methods are extremely hard to read and maintain. Break them into smaller helper methods if needed.
• Limit parameters: Ideal number of parameters for a method is less than 3. If more, reconsider breaking method into smaller ones.
• Use descriptive names: Method names should clearly indicate what the method does. Use verbal phrases like calculateTotal or getMaxPrice.
• Return empty collections instead of null: Return empty List, Map or Set instead of returning null to avoid NullPointerExceptions.
• Use exceptions instead of return codes: Instead of returning error codes, throw exceptions to handle errors.
• Avoid side effects: Don’t use methods that modify state. Isolate side-effects from main logic.

Writing clean methods that follow single responsibility principle allows better testability and prevents unexpected behavior.

Exceptions Handling

Here are some Java best practices to follow for exception handling:

• Include try/catch blocks: Use try/catch blocks instead of throwing Exception. It makes call sites cleaner.
• Catch specific exceptions: Instead of using Exception class, catch and handle specific exceptions when possible for cleaner code.
• Print stack traces: Log exception messages along with stack trace for debugging production issues.
• Don’t swallow exceptions: Don’t catch Exception without handling or rethrowing as it silently swallows issues.
• Use finally: Use finally blocks to ensure critical code executes even if exception was thrown.
• Rethrow appropriate exceptions: Wrap caught exceptions in custom exception class if context needs to be added while rethrowing.

Proper exception handling with descriptive errors leads to robust code capable of gracefully handling edge cases.

Concurrency

Make use of Java’s strong concurrency features to refine the responsiveness and performance of your applications. To maximize the performance and scalability of your project, use threads to handle parallel operations efficiently and hire Java developers with concurrent programming experience.

Here are some Java concurrency best practices:

• Favor higher level abstractions: Use abstractions like Executors and Callable over low level threading with Thread class.
• Use synchronized blocks carefully: Use object level synchronized blocks judiciously over using synchronized method.
• Prefer concurrent collections: Use classes like ConcurrentHashMap and CopyOnWriteArrayList over synchronized collections.
• Avoid memory consistency errors: Understand Java memory model well to avoid visibility and race conditions bugs.
• Use thread pools: Reuse threads with thread pools instead of creating new threads every time for better performance.
• Use volatile for visibility: Use volatile variables when multiple threads need access to shared state.

Writing concurrent Java code is tricky! Following these best practices from the start helps avoid nasty multi-threading bugs later.

Working with Collections

Java offers excellent Collections of Java Framework. Here are some best practices to leverage it effectively:

• Return zero-length collections: Return empty List/Set instead of nulls to avoid NPEs.
• Use generics for type-safety: Parameterize your custom collection classes and methods with generics for typesafety.
• Favor foreach loops: Enhanced for-each style loops prevent bugs/exceptions compared to Iterator.
• Use collection interfaces: Code against interfaces like List and Set instead of concrete classes like ArrayList.
• Avoid inefficient operations: Avoid inefficient operations like sublist on an ArrayList or excessive growth.

Java collections are very handy but have their own set of pitfalls. Following best practices leads to optimal utilization of Java Collections Framework.

Using Streams API

Here are some Java 8 Streams API best practices:

• No side effects in stream operations: Don’t modify state in stream operations. Keep operations free of side-effects.
• Avoid too many intermediate operations: Use no more than four or five intermediate operations in a stream pipeline for optimal performance.
• Watch for performance with large data sets: Certain operations like sorted() can severely impact performance with large data sets.
• Use primitive type streams when possible: Primitive type streams like IntStream avoid boxing costs associated with generic streams.
• Limit nested streams: Nesting many streams can affect readability and performance. Use flatMap instead of nesting many layers.

The Streams API allows writing concise yet complex data processing queries on collections. Following best practices prevents misuse and undesired behavior.

Writing Clean Code

Here are some high-level practices that lead to cleaner Java code:

• Follow Java naming conventions & styles detailed before
• Modularize code: Break code into separate reusable classes and interfaces by functionality
• Remove dead/unused code: Delete unused code blocks instead of just commenting them out
• Avoid premature optimization: Focus on clean, readable and maintainable code before performance optimizations
• Add detailed comments: Use Javadoc style comments for classes, interfaces, methods explaining logic where it makes sense
• Limit scope of instance variables: Declare variables with the minimum scope needed instead of constantly as class fields

Conclusion

That wraps up our comprehensive guide to Java best practices!

As a Java developer, following these code formatting, naming, modularity, exception handling, concurrency, collections and commenting best practices will drastically improve quality of your code. Clean, efficient and maintainable code is essential for delivering robust software systems capable of evolving over time.

Adopting these Java best practices takes some time but pays huge dividends through enhanced productivity that translates to faster delivery of business value.

So, start refactoring your legacy code or developing new features incorporating these learnings for long term gains. Your dedicated development team and clients will appreciate maintainable, testable code delivered faster with fewer bugs!