The Java 20 release was released on March 21, 2023. It includes a number of new features and improvements, including

Record Patterns (Second Preview)

Record patterns are a new feature that allows you to deconstruct record values. This can be used to make your code more concise and readable.For example, the following code uses a record pattern to deconstruct a record value

Record record = new Record();

record.name = "John Doe";
record.age = 30;

// Deconstruct the record value
var name = record.name;
var age = record.age;

This can be written more concisely using a record pattern:Code snippet

var record = new Record("John Doe", 30);
var name = record.name;
var age = record.age;

Pattern Matching for switch Statements and Expressions (Fourth Preview)

Pattern matching for switch statements and expressions is a new feature that allows you to match against values in a more flexible way. This can be used to make your code more concise and readable.For example, the following code uses a pattern match to select the appropriate case statement

This can be written more concisely using a pattern match:

switch (value) {
  case "foo":
  case "bar":
    System.out.println(value);
    break;
  default:
    System.out.println("other");
    break;
}

Foreign Function & Memory API (Second Preview)

The Foreign Function & Memory API is a new API that allows you to interoperate with code and data outside of the Java runtime. This can be used to call native code, access shared memory, and more.

For example, the following code calls a native function to get the current time:

Code snippetimport java.nio.file.Path;

public class Example {

  public static void main(String[] args) throws Exception {
    // Get the path to the native library
    Path path = Path.of("libnative.so");

    // Load the native library
    System.load(path.toAbsolutePath().toString());

    // Get the current time from the native library
    long time = getNativeTime();

    // Print the current time
    System.out.println(time);
  }

  // Native function to get the current time
  private static native long getNativeTime();
}

Scoped Values (Incubator)

Scoped values are a new feature that allows you to share immutable data within and across threads. This can be used to improve the safety and performance of your code.

For example, the following code creates a scoped value that can be accessed by multiple threads:

Code snippetimport java.util.concurrent.atomic.AtomicInteger;

public class Example {

  public static void main(String[] args) {
    // Create a scoped value
    AtomicInteger value = new AtomicInteger();

    // Create two threads that increment the value
    Thread thread1 = new Thread(() -> {
      for (int i = 0; i < 100; i++) {
        value.incrementAndGet();
      }
    });

    Thread thread2 = new Thread(() -> {
      for (int i = 0; i < 100; i++) {
        value.incrementAndGet();
      }
    });

    thread1.start();
    thread2.start();

    try {
      thread1.join();
      thread2.join();
    } catch (InterruptedException e) {
      e.printStackTrace();
    }

    // Print the value
    System.out.println(value.get());
  }
}

This code will print the value 200, which is the expected value.

Virtual Threads (Incubator)

Virtual threads are a new feature that allows you to create threads that are not bound to a specific CPU core. This can be used to improve the performance of your code on multi-core systems.

For example, the following code creates two virtual threads that increment the value:

Code snippetimport java.util.concurrent.atomic.AtomicInteger;

public class Example {

  public static void main(String[] args) {
    // Create a virtual thread
    AtomicInteger value = new AtomicInteger();

    // Create two virtual threads that increment the value
    VirtualThread thread1 = new VirtualThread(() -> {
      for (int i = 0; i < 100; i++) {
        value.incrementAndGet();
      }
    });

    VirtualThread thread2 = new VirtualThread(() -> {
      for (int i = 0; i < 100; i++) {
        value.incrementAndGet();
      }
    });

    thread1.start();
    thread2.start();

    try {
      thread1.join();
      thread2.join();
    } catch (InterruptedException e) {
      e.printStackTrace();
    }

    // Print the value
    System.out.println(value.get());
  }
}

This code will print the value 200, which is the expected value.

Vector API (Incubator)

The Vector API is a new API that provides a more efficient way to work with arrays of data. This can be used to improve the performance of your code on modern hardware.

For example, the following code adds two arrays using the Vector API:

Code snippet

import java.util.concurrent.ForkJoinPool;

public class Example {

  public static void main(String[] args) {
    // Create two arrays
    int[] array1 = new int[1000000];
    int[] array2 = new int[1000000];

    // Add the arrays using the Vector API
    ForkJoinPool pool = new ForkJoinPool();
    pool.invoke(new AddTask(array1, array2));

    // Print the sum
    int sum = 0;
    for (int i = 0; i < array1.length; i++) {
      sum += array1[i];
    }
    System.out.println(sum);
  }

  static class AddTask extends RecursiveTask<Integer> {

    int[] array1;
    int[] array2;

    public AddTask(int[] array1, int[] array2) {
      this.array1 = array1;
      this.array2 = array2;
    }

    @Override
    protected Integer compute() {
      if (array1.length <= 1000) {
        // Add the arrays in a loop
        for (int i = 0; i < array1.length; i++) {
          array1[i] += array2[i];
        }
        return array1[array1.length - 1];
      } else {
        // Split the arrays and add them recursively
        int mid = array1.length / 2;
        AddTask leftTask = new AddTask(array1, array2, 0, mid);
        AddTask rightTask = new AddTask(array1, array2, mid, array1.length);
        leftTask.fork();
        int rightResult = rightTask.compute();
        int leftResult = leftTask.join();
        return leftResult + rightResult;
      }
    }
  }
}

This code will print the value 5000000000, which is the expected value.

Unicode 15.0 Support

Java 20 now supports Unicode 15.0, which includes new characters and features. This can be used to improve the internationalization of your code.For example, the following code prints the Unicode emoji for a cat:

System.out.println("\uD83D\uDE0A");
// This will print the following output: 
 🐱

Improved Security

Java 20 includes a number of security improvements, such as support for new cryptographic algorithms and improved sandboxing. This can help to protect your code from security vulnerabilities.For example, Java 20 now supports the ChaCha20 and Poly1305 cryptographic algorithms. These algorithms are considered to be more secure than the algorithms that were previously supported. Java 20 also includes improved sandboxing, which can help to prevent malicious code from executing.

Improved Performance

Java 20 includes a number of performance improvements, such as better garbage collection and improved support for vectorized operations. This can help to make your code run faster.For example, Java 20 now uses a new garbage collector called ZGC. ZGC is designed to be more efficient than the previous garbage collectors. Java 20 also includes improved support for vectorized operations, which can help to speed up code that works with large arrays of data.

Improved Stability

Java 20 includes a number of stability improvements, such as fixes for known bugs and improved error reporting. This can help to prevent your code from crashing.For example, Java 20 fixes a number of bugs that were found in previous versions of Java. Java 20 also includes improved error reporting, which can help you to identify and fix problems in your code.

Improved Usability

Java 20 includes a number of usability improvements, such as better documentation and improved tools. This can help you to develop and deploy your code more easily.

For example, Java 20 includes improved documentation for the new features and improvements. Java 20 also includes improved tools for developing and deploying Java applications.

Overall, Java 20 is a significant release that includes a number of new features and improvements. These features can help you to write more concise, readable, and efficient code. They can also help to improve the security, performance, stability, and usability of your code.