thpeetz-notes/Clippings/3 Advanced Java Best Practices.md

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3 Advanced Java Best Practices	https://orlandolorenzodeveloper.medium.com/3-advances-java-best-practices-ac7d02a55432	Lorenzo Orlando	2024-10-01	2024-10-29	Hello everyone, today we’re diving deep in some advanced Java best practices. Let’s start right away. Java 8 introduced streams and lambda expressions, which allow for cleaner, functional-style code…	clippings

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Hello everyone, today we’re diving deep in some advanced Java best practices. Let’s start right away.

1. Use Streams and Lambda Expressions Efficiently

Why?

Java 8 introduced streams and lambda expressions, which allow for cleaner, functional-style code. While they are powerful, improper use can lead to performance overhead and complexity.

Best Practices:

• Avoid creating multiple intermediate Stream operations like filter() and map() if not necessary, as they can add overhead.
• Leverage parallel streams for CPU-bound tasks but avoid them for I/O-bound tasks (due to context switching).
• Prefer **forEach()** for side effects like logging, but use terminal operations like collect() for transforming data.

Example

List<String> names = employees.stream()                              .filter(e -> e.getAge() > 30)                              .map(Employee::getName)                              .collect(Collectors.toList());

2. Minimize Synchronization and Leverage Concurrency Utilities

Why?

Java provides a rich set of concurrency utilities like ExecutorService, ForkJoinPool, and CompletableFuture. Using these properly avoids blocking and bottlenecks in multi-threaded applications.

Best Practices:

• Use **ConcurrentHashMap** over synchronized collections for thread-safe operations with better performance.
• Utilize optimistic locking (e.g., java.util.concurrent.atomic package) instead of traditional synchronized blocks.
• Leverage non-blocking algorithms and modern concurrency utilities like CompletableFuture for asynchronous processing.

Example

CompletableFuture<Void> future = CompletableFuture.runAsync(() -> {    processData();}, executorService);

3. Apply Design Patterns and Immutability Smartly

Why?

Design patterns like Singleton, Factory, and Builder ensure better object management, while immutability improves thread-safety and reduces side effects.

Best Practices:

• Ensure immutability in frequently used objects to make them thread-safe without requiring synchronization.
• Use Factory Pattern to encapsulate object creation, making the code more flexible and testable.
• Apply the Builder Pattern for constructing complex objects, making the code cleaner and avoiding telescoping constructors.

Example

public class User {    private final String name;    private final int age;    private User(Builder builder) {        this.name = builder.name;        this.age = builder.age;    }    public static class Builder {        private String name;        private int age;        public Builder withName(String name) {            this.name = name;            return this;        }        public Builder withAge(int age) {            this.age = age;            return this;        }        public User build() {            return new User(this);        }    }}User user = new User.Builder().withName("John").withAge(25).build();