10 Ways Java 20 Will Make You a Better Programmer

Java 20 introduces pattern matching, record patterns, enhanced random generators, Foreign Function & Memory API, Vector API, virtual threads, and Sequenced Collections. These features improve code readability, performance, and concurrency.

Jul 6, 2023

10 Ways Java 20 Will Make You a Better Programmer

Java 20 is here, and it’s packed with exciting features that’ll take your programming skills to the next level. Let’s dive into how this latest release can make you a better coder.

First up, we’ve got pattern matching for switch statements. This nifty addition lets you write more expressive and concise code. Instead of long, nested if-else chains, you can now use switch statements with patterns. It’s like giving your code a makeover – cleaner and easier to read.

Here’s a quick example:

Object obj = // some object
switch (obj) {
    case Integer i -> System.out.println("It's an integer: " + i);
    case String s -> System.out.println("It's a string: " + s);
    case List<String> list -> System.out.println("It's a list of strings: " + list);
    default -> System.out.println("It's something else");
}

Pretty neat, right? This feature alone can make your code more readable and maintainable. But wait, there’s more!

Java 20 introduces record patterns, which work hand in hand with pattern matching. Records, introduced in Java 14, are great for creating simple data carrier classes. Now, with record patterns, you can destructure records in a single step. It’s like unwrapping a present – you get all the goodies inside with minimal effort.

Check out this example:

record Point(int x, int y) {}
record Rectangle(Point upperLeft, Point lowerRight) {}

Rectangle r = new Rectangle(new Point(1, 2), new Point(3, 4));
if (r instanceof Rectangle(Point(int x1, int y1), Point(int x2, int y2))) {
    System.out.println("Upper left: (" + x1 + ", " + y1 + ")");
    System.out.println("Lower right: (" + x2 + ", " + y2 + ")");
}

This feature is a game-changer for working with complex data structures. It makes your code more expressive and reduces the chance of errors when accessing nested data.

Now, let’s talk about the enhanced pseudo-random number generators. Java 20 introduces new interfaces and implementations for generating random numbers. This might sound boring, but trust me, it’s cool. You get more control over the algorithms used, which is super important for things like simulations and cryptography.

Here’s a simple example of using the new random number generators:

RandomGenerator generator = RandomGenerator.of("L64X128MixRandom");
int randomNumber = generator.nextInt(100); // Random number between 0 and 99

This feature gives you more flexibility and power when working with randomness in your programs. It’s like having a swiss army knife for random numbers – you’ve got the right tool for every job.

Java 20 also brings improvements to the Foreign Function & Memory API. This API allows Java programs to interact more easily with code and data outside of the Java runtime. It’s still a preview feature, but it’s worth getting familiar with. Imagine being able to call C functions directly from Java, or work with off-heap memory – that’s what this API enables.

Here’s a taste of what you can do:

// Calling a C function from Java
try (Arena arena = Arena.openConfined()) {
    MemorySegment cString = arena.allocateUtf8String("Hello, C!");
    MemorySegment result = linker.downcallHandle(
        lookup.find("puts"),
        FunctionDescriptor.of(ValueLayout.JAVA_INT, ValueLayout.ADDRESS)
    ).invoke(cString);
    System.out.println("C function returned: " + result.toRawLongValue());
}

This feature opens up a whole new world of possibilities for Java developers. You can now write high-performance code that interacts directly with system libraries or manages memory more efficiently.

Next up, we’ve got the Vector API. This is another preview feature that’s been evolving over several Java releases. It allows you to express vector computations that reliably compile to optimal vector instructions on supported CPU architectures. In simpler terms, it helps you write faster code for number crunching tasks.

Here’s a simple example of using the Vector API:

static final VectorSpecies<Float> SPECIES = FloatVector.SPECIES_256;

void vectorComputation(float[] a, float[] b, float[] c) {
    for (int i = 0; i < a.length; i += SPECIES.length()) {
        var va = FloatVector.fromArray(SPECIES, a, i);
        var vb = FloatVector.fromArray(SPECIES, b, i);
        var vc = va.mul(vb);
        vc.intoArray(c, i);
    }
}

This API is a big deal for anyone working on performance-critical applications. It allows you to take full advantage of modern CPU capabilities, potentially speeding up your code significantly.

Java 20 also continues to improve the Project Loom features, including virtual threads and structured concurrency. These features are set to revolutionize how we write concurrent code in Java. Virtual threads make it possible to write highly scalable applications with a familiar programming model.

Here’s a quick example of using virtual threads:

try (var executor = Executors.newVirtualThreadPerTaskExecutor()) {
    IntStream.range(0, 10_000).forEach(i -> {
        executor.submit(() -> {
            Thread.sleep(Duration.ofSeconds(1));
            return i;
        });
    });
}

This code creates 10,000 virtual threads, each sleeping for a second. With platform threads, this would be a resource nightmare. But with virtual threads, it’s a breeze. This feature alone can dramatically simplify how you write concurrent code.

The JDK also continues to evolve its support for modern programming paradigms. For instance, the introduction of the Sequenced Collections interface provides a standard way to work with collections that have a defined encounter order. This might seem like a small change, but it can make your code more expressive and less error-prone.

Here’s how you might use it:

SequencedCollection<String> list = new ArrayList<>(List.of("a", "b", "c"));
String first = list.getFirst();
String last = list.getLast();
list.addFirst("z");
list.addLast("d");

This interface provides a consistent way to work with the first and last elements of ordered collections, making your code more intuitive and easier to read.

Java 20 also brings improvements to the language’s type system. While not as flashy as some other features, these improvements help catch more errors at compile-time, reducing the likelihood of runtime errors. For example, there are ongoing efforts to improve type inference and make generics more powerful.

Lastly, let’s talk about the continued improvements to the GC (Garbage Collector) and JIT (Just-In-Time) compiler. These under-the-hood enhancements might not change how you write code, but they can significantly impact your application’s performance. The ZGC (Z Garbage Collector) and Shenandoah GC continue to evolve, providing better pause times and overall performance for large heap sizes.

In conclusion, Java 20 is packed with features that can make you a better programmer. From more expressive language constructs like pattern matching and record patterns to powerful APIs for working with native code and vector operations, there’s something for everyone. The improvements to concurrency with virtual threads and structured concurrency are set to change how we think about writing scalable applications.

As a Java developer, staying up-to-date with these features is crucial. They not only make your code more efficient and expressive but also open up new possibilities for what you can achieve with Java. So dive in, experiment with these new features, and watch your programming skills level up. Happy coding!