Java 17, released as a Long-Term Support (LTS) version, brings several exciting new features that improve performance, security, and developer productivity. These changes include enhancements to the language, the introduction of new APIs, and performance improvements that make Java 17 a solid choice for both enterprise applications and modern development practices. In this article, we will explore the key features in Java 17 and how they benefit developers.
1. Sealed Classes
One of the most anticipated features in Java 17 is sealed classes. Sealed classes allow developers to define a restricted set of subclasses, offering better control over class hierarchies. This feature improves maintainability, readability, and safety when designing class hierarchies by restricting which classes or interfaces can extend or implement them.
Example:
public sealed class Vehicle permits Car, Truck { }
public final class Car extends Vehicle { }
public final class Truck extends Vehicle { }
With sealed classes, you can ensure that only certain classes inherit from a superclass, making your design more predictable.
2. Pattern Matching for switch (Preview)
Java 17 introduces Pattern Matching for switch as a preview feature. This enhancement simplifies the use of switch statements by allowing patterns to be used in case labels. Pattern matching makes code more readable and reduces the need for explicit type casting.
Example:
public static String getShapeType(Object shape) {
return switch (shape) {
case Circle c -> "Circle with radius " + c.radius();
case Rectangle r -> "Rectangle with width " + r.width() + " and height " + r.height();
default -> "Unknown shape";
};
}
This feature improves code clarity and reduces boilerplate when dealing with complex object hierarchies in switch statements.
3. Stronger Encapsulation with JDK Internals
In Java 17, JDK internals that were previously accessible via reflection are now strongly encapsulated. This improves security and maintainability by preventing access to JDK internals that were not intended for external use.
The --illegal-access option is no longer available, which means any code that relies on accessing JDK internals via reflection will break. This change encourages developers to migrate to supported APIs, improving long-term code stability.
4. New macOS Rendering Pipeline (JEP 382)
Java 17 introduces a new macOS rendering pipeline based on Apple’s Metal framework, replacing the older OpenGL pipeline. This change improves performance on macOS systems by providing more efficient graphics rendering.
Benefits:
- Faster and more efficient rendering on macOS devices.
- Better integration with the latest macOS hardware.
- Future-proofing the graphics layer for Apple’s ecosystem.
This change is part of ongoing efforts to improve Java’s performance on different platforms and provide a better user experience on modern systems.
5. JEP 356: Enhanced Pseudo-Random Number Generators (PRNGs)
Java 17 introduces enhanced pseudo-random number generators (PRNGs), providing a more robust API for generating random numbers. This new API includes support for stream-based APIs and new algorithms like LXM, which offer better statistical properties for certain applications.
Example:
RandomGenerator random = RandomGenerator.of("L64X128MixRandom");
System.out.println(random.nextInt());
These improvements enhance randomness quality, particularly for applications requiring secure random numbers or better distribution for simulations.
6. JEP 382: New macOS Rendering Pipeline (Preview)
The new macOS rendering pipeline based on Apple’s Metal API improves the performance of Java applications on macOS systems. This change is part of Java’s efforts to optimize cross-platform performance, ensuring better responsiveness and efficiency on Apple devices.
Benefits:
- Improved rendering speed and graphics performance.
- Better integration with macOS hardware for native-level efficiency.
7. JEP 411: Deprecate the Security Manager for Removal
Java 17 has deprecated the Security Manager for removal. The Security Manager, which was used for controlling security policies in Java applications, has been in use for many years but is now considered outdated and no longer suitable for modern cloud and containerized environments.
Implications:
- The deprecation of the Security Manager signals a shift towards using more modern security practices.
- Developers are encouraged to migrate towards other security frameworks, like JVM-based security policies or container security features.
8. JEP 376: ZGC (Z Garbage Collector) on macOS
Java 17 also brings ZGC (Z Garbage Collector) support to macOS, improving memory management and performance for applications with large heap sizes. ZGC is a low-latency garbage collector designed to minimize pauses, making it ideal for real-time and large-scale applications.
Benefits of ZGC:
- Low-latency garbage collection.
- Improved performance for applications with large heaps or long-running processes.
9. New APIs in Java 17
In addition to these language and performance enhancements, Java 17 introduces several new APIs to make development easier and more powerful:
- Foreign Function & Memory API: An API for working with native memory and calling native code outside the JVM.
- Vector API: A new API for vector computation, offering better performance for certain workloads.
- Enhanced JDK Flight Recorder: Expanded support for monitoring and troubleshooting applications at runtime.
Conclusion
Java 17 brings a wealth of new features that significantly enhance the language and APIs, offering more powerful tools for developers. From sealed classes and pattern matching to improvements in garbage collection and rendering pipelines, these features provide better performance, security, and maintainability. As a Long-Term Support (LTS) release, Java 17 offers stability and robust new features for modern application development. Developers looking to take advantage of these features will find that Java 17 is a great foundation for building reliable, high-performance applications.
