Is Java 8 Dead? Discover All New Features from Java 8 to Java 24

Java 8 Essentials

Java 8 introduced functional programming to the language with lambda expressions and the Stream API, dramatically simplifying collection processing and enabling concise code.

// Lambda example before Java 8
button.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent e) {
        System.out.println("Button clicked");
    }
});

// Lambda in Java 8
button.addActionListener(e -> System.out.println("Button clicked"));

The Stream API allows fluent operations like filter, map, and collect to process data pipelines efficiently.

List<String> result = words.stream()
    .filter(w -> w.length() > 5)
    .map(String::toUpperCase)
    .sorted()
    .collect(Collectors.toList());

Java 9–13: Modules and Preview Features

Java 9 added the module system, letting developers declare explicit dependencies in module-info.java. Subsequent releases introduced preview features such as switch expressions and text blocks.

// module-info.java example
module user.management {
    exports com.company.user.service;
    requires java.base;
    requires database.connection;
}

Java 11: Modern HTTP Client

Java 11 standardized an HTTP client API that supports synchronous and asynchronous requests, HTTP/2, and WebSocket communication.

HttpClient client = HttpClient.newBuilder()
    .connectTimeout(Duration.ofSeconds(10))
    .build();
HttpRequest request = HttpRequest.newBuilder()
    .uri(URI.create("https://example.com"))
    .GET()
    .build();
HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());

Java 14: Switch Expressions

Switch became an expression, allowing multiple case labels and returning values with yield.

String dayType = switch (day) {
    case MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY -> "Workday";
    case SATURDAY, SUNDAY -> "Weekend";
    default -> "Unknown";
};
int score = switch (grade) {
    case 'A' -> { System.out.println("Excellent"); yield 90; }
    case 'B' -> 80;
    default -> 0;
};

Java 16: Records

Records provide a compact syntax for immutable data carriers, automatically generating constructors, accessors, equals, hashCode, and toString.

public record Person(String name, int age, String email) {}

Person p = new Person("Yupi", 25, "[email protected]");
System.out.println(p.name()); // Yupi

Java 17: Sealed Classes and Virtual Threads

Sealed classes restrict which subclasses may extend a class, improving pattern‑matching safety. Virtual threads (Project Loom) enable lightweight concurrency with dramatically lower overhead.

// Sealed hierarchy
public sealed class Shape permits Circle, Rectangle, Triangle {}
public final class Circle extends Shape {}
public non-sealed class Rectangle extends Shape {}

// Virtual thread example
try (var executor = Executors.newVirtualThreadPerTaskExecutor()) {
    for (int i = 0; i < 1000; i++) {
        executor.submit(() -> {
            String r = httpClient.get("https://codefather.cn");
            System.out.println("Response: " + r);
        });
    }
}

Java 24: Stream Gatherers

Gatherers extend the Stream API with stateful collectors such as sliding windows.

List<Double> prices = List.of(100.0, 102.0, 98.0, 105.0, 110.0);
List<Double> movingAverages = prices.stream()
    .gather(Gatherers.windowSliding(3))
    .map(w -> w.stream().mapToDouble(Double::doubleValue).average().orElse(0.0))
    .toList();
System.out.println(movingAverages); // [100.0, 101.666..., 104.333...]