Java 17: What’s New and How It Will Change Your Coding

Java 17, the latest Long-Term Support (LTS) release of Java, brings a host of new features, enhancements, and deprecations that promise to improve the developer experience and application performance. As developers, staying updated with these changes is crucial to leverage the full potential of the language and maintain best practices. In this blog, we’ll explore the key features introduced in Java 17, complete with examples and insights on how they can impact your coding.

1. Sealed Classes

Sealed classes introduce a new way to control class hierarchies. By restricting which classes can be extended or implemented, sealed classes enhance encapsulation and improve code readability.

public abstract sealed class Shape permits Circle, Square {}

public final class Circle extends Shape {
    // Implementation
}

public final class Square extends Shape {
    // Implementation
}

In this example, the Shape class can only be extended by Circle and Square. Any attempt to extend it with another class will result in a compilation error.

2. Pattern Matching for Switch (Preview)

Pattern matching simplifies code by allowing you to extract components from objects more succinctly. Java 17 extends this capability to switch statements.

Example:

public String formatShape(Shape shape) {
    return switch (shape) {
        case Circle c -> String.format("Circle with radius %f", c.radius());
        case Square s -> String.format("Square with side %f", s.side());
        default -> throw new IllegalStateException("Unexpected value: " + shape);
    };
}

This pattern-matching syntax makes the code more concise and readable.

3. Enhanced Pseudo-Random Number Generators

Java 17 introduces new interfaces and implementations for random number generation, enhancing flexibility and performance.

Example:

import java.util.random.RandomGenerator;
import java.util.random.RandomGeneratorFactory;
public class RandomExample {
    public static void main(String[] args) {
        RandomGenerator generator = RandomGeneratorFactory.of("L128X256MixRandom").create();
        System.out.println(generator.nextInt());
    }
}

This code demonstrates the use of the new RandomGenerator interface to generate random numbers.

4. Deprecations and Removals

Java 17 removes and deprecates several outdated features, encouraging developers to use more modern alternatives. Notably, the experimental AOT and JIT compilers have been removed.

Removed Features:

• Experimental AOT and JIT Compilers: These compilers were rarely used and their removal simplifies the JDK.
• RMI Activation: The Remote Method Invocation (RMI) Activation mechanism is removed due to low usage and the availability of more modern alternatives.

Deprecated Features:

• Applets: Applets have been deprecated and their support in modern browsers is minimal. Use modern web technologies like HTML5 and JavaScript instead.
• Security Manager: The Security Manager is deprecated for removal in a future release. Applications should use modern security practices and frameworks.

5. Strong Encapsulation in the JDK

Encapsulation enhancements restrict access to internal APIs, promoting better security and stability. Modules now require explicit exports for reflective access.

Example:

module my.module {
    exports com.example.myapp;
}

This module declaration explicitly exports the com.example.myapp package, ensuring only intended packages are accessible.

How Java 17 Will Change Your Coding

1. Improved Code Quality: Features like sealed classes and pattern matching for switches enable cleaner, more maintainable code.
2. Enhanced Performance: The new random number generators and other performance enhancements can lead to more efficient applications.
3. Better Security: Strong encapsulation and the removal of deprecated features ensure a more secure codebase.
4. Future-Proofing: Adopting the latest language features prepares your code for future Java versions, reducing technical debt.

Conclusion

Java 17 brings significant advancements that can transform how you write and maintain your code. By leveraging these new features, you can create more robust, efficient, and secure applications. Stay tuned for more in-depth guides and examples on Java 17 and beyond!