Empowering Java Developers: JDK 21 Unleashes New Possibilities

Definitely! In this article, we'll take a look at the new features in JDK 21, which are designed to make Java programming easier and more efficient. These features have been proposed as part of the Java Community Process (JSR 396). Let us know them in a simple way.

1. String Templates (Preview):

Imagine you want to create complex text with variable values in Java. In older versions, you had to use lots of plus signs and other operations to build the string. But in JDK 21, they've introduced something called "String Templates." These templates allow you to directly put variables into your text using ${}. This makes your code cleaner and easier to read.

Let’s explore a different example to showcase the power of string templates in performing advanced formatting. Consider a scenario where you want to display. Traditionally, you might concatenate multiple strings using the + operator:

// Before JDK 21
String name = "Alice";
String greeting = "Hello, " + name + "!";

// With String Templates in JDK 21
String name = "Alice";
String greeting = `Hello, ${name}!`;
        

2. Sequenced Collections:

In Java, we often work with collections like lists and sets. JDK 21 introduces a way to make it easier to access the first and last elements in these collections. Before, you had to use different methods for different types of collections. Now, there are consistent methods to get the first and last elements, making your code more straightforward.

// Before JDK 21
List<String> names = new ArrayList<>();
String firstName = names.get(0);
String lastName = names.get(names.size() - 1);

// With Sequenced Collections in JDK 21
List<String> names = new ArrayList<>();
String firstName = names.getFirst();
String lastName = names.getLast();        

3. Record Patterns:

Records are a way to define simple classes for storing data. In JDK 21, they've made it even easier to work with records by introducing "Record Patterns." This allows you to extract values from records in a more direct way, without needing extra code to access their components.

// Before JDK 21
record Point(int x, int y) {}

static void printSum(Object obj) {
    if (obj instanceof Point p) {
        int x = p.x();
        int y = p.y();
        System.out.println(x + y);
    }
}

// With Record Patterns in JDK 21
static void printSum(Object obj) {
    if (obj instanceof Point(int x, int y)) {
        System.out.println(x + y);
    }
}        

4. Pattern Matching for Switch:

Pattern matching for switch statements is another feature in JDK 21. It simplifies complex data checks and actions. Instead of multiple if-else statements, you can use switch with patterns, making your code cleaner and more reliable.

// Before JDK 21
static String format(Object obj) {
    String formatted = "unknown";
    if (obj instanceof Integer i) {
        formatted = "int " + i;
    } else if (obj instanceof Long l) {
        formatted = "long " + l;
    } else if (obj instanceof Double d) {
        formatted = "double " + d;
    } else if (obj instanceof String s) {
        formatted = "String " + s;
    }
    return formatted;
}

// With Pattern Matching for Switch in JDK 21
static String format(Object obj) {
    return switch (obj) {
        case Integer i -> "int " + i;
        case Long l -> "long " + l;
        case Double d -> "double " + d;
        case String s -> "String " + s;
        default -> "unknown";
    };
}        

5. Unix Domain Sockets: Java 21 introduces support for Unix domain sockets, enabling communication between processes on the same machine. This feature facilitates interprocess communication and enhances the development of scalable and efficient applications.

6. Foreign Function & Memory API (Incubator): The Foreign Function & Memory API, an incubator feature in Java 21, allows Java programs to call and interact with native code more easily and efficiently. It provides a standardised mechanism for accessing native memory, enhancing performance and interoperability.

7. ZGC Improvements: Java 21 brings further improvements to the Z Garbage Collector (ZGC), a low-latency garbage collector. The enhancements include lower latency, improved throughput, and better scalability. These improvements make Java applications more responsive and efficient, particularly in large-scale deployments.

8. Enhanced Pseudo-Random Number Generators: Java 21 introduces enhanced support for pseudo-random number generation with the introduction of the java.util.random package. This package provides more secure and high-quality random number generation capabilities, crucial for applications that require robust randomness.

9. Deprecation of Applet API: The Applet API, which has been deprecated since Java 9, is finally removed in Java 21. This removal reflects the industry shift away from browser-based applets and encourages the use of modern web technologies for building web applications.

Java 21 introduces a range of powerful features and enhancements that empower developers to write cleaner, more efficient, and more secure code. From pattern matching for switching expressions and records to sealed classes and text blocks, these features simplify coding tasks and enhance readability. The addition of Unix domain sockets, the Foreign Function & Memory API, and ZGC improvements further enhance performance, scalability, and interoperability. As Java continues to evolve, developers can leverage these new features to build robust and innovative applications. So, embrace the power of Java 21 and unlock its full potential in your next project.

References : https://www.oracle.com/java/technologies/javase/21-relnote-issues.html