Java 8, Java 11, Java 17 Features: Complete Guide

Java has evolved significantly with each release. Java 8 introduced functional programming, Java 11 improved performance and added new APIs, and Java 17 (LTS) brought modern language enhancements.

Java 8 Features

Java 8 is one of the most important releases, introducing functional programming concepts.

1. Lambda Expressions

Lambda expressions allow writing shorter code for functional interfaces.

List list = Arrays.asList(1,2,3);

list.forEach(n -> System.out.println(n));

2. Functional Interfaces

An interface with a single abstract method.

@FunctionalInterface
interface Test {
    void display();
}

3. Stream API

Used to process collections efficiently.

list.stream()
    .filter(n -> n % 2 == 0)
    .forEach(System.out::println);

4. Default Methods

Interfaces can have method implementations.

interface A {
    default void show() {
        System.out.println("Default Method");
    }
}

5. Optional Class

Avoids NullPointerException.

Optional name = Optional.ofNullable(null);
System.out.println(name.orElse("Default"));

6. Date & Time API

LocalDate date = LocalDate.now();
System.out.println(date);

Java 11 Features

Java 11 is a Long-Term Support (LTS) version with performance and API improvements.

1. var Keyword (Local Variables)

var message = "Hello Java 11";
System.out.println(message);

2. New String Methods

• isBlank()
• lines()
• repeat()

"Java".repeat(3);

3. HTTP Client API

HttpClient client = HttpClient.newHttpClient();

4. Files API Improvements

String content = Files.readString(Path.of("file.txt"));

5. Removed Java EE Modules

Modules like JAXB removed from JDK.

Java 17 Features (LTS)

Java 17 is a modern LTS version with improved performance and new language features.

1. Sealed Classes

Restrict which classes can extend or implement a class.

public sealed class Shape
    permits Circle, Square { }

2. Records

Compact way to create immutable data classes.

record Person(String name, int age) { }

3. Pattern Matching for instanceof

if (obj instanceof String s) {
    System.out.println(s.length());
}

4. Switch Enhancements

int day = 2;

String result = switch(day) {
    case 1 -> "Monday";
    case 2 -> "Tuesday";
    default -> "Other";
};

5. Improved Garbage Collection

Better performance and memory management.

Java 8 vs 11 vs 17 Comparison

Java Features FAQ

Which Java version is best?

Java 17 is recommended as it is the latest LTS version.

Why Java 8 is popular?

Because of Lambda, Streams, and functional programming.

What is LTS version?

Long-Term Support versions are stable and supported for a long time.