Everything New from Java 8 to Java 25 (LTS Releases)

Java has evolved significantly over the last decade, introducing features that improve readability, performance, concurrency, and developer productivity.

This article covers the most important additions introduced in the five Long-Term Support (LTS) releases: Java 8, Java 11, Java 17, Java 21, and Java 25.

Java 8 (LTS)

Java 8 was one of the biggest releases in Java's history.

It introduced functional programming, the Streams API, CompletableFuture, and the modern Date & Time API, fundamentally changing how Java applications are written today.

Lambda Expressions

Lambda expressions provide a concise way to represent anonymous functions, making the code more readable and reducing boilerplate.

Before Java 8

Collections.sort(names, new Comparator<String>() {
    @Override
    public int compare(String a, String b) {
        return a.compareTo(b);
    }
});

Java 8

Collections.sort(names, (a, b) -> a.compareTo(b));

Lambdas are widely used with Streams, Collections, and functional interfaces.

Functional Interfaces

A functional interface contains exactly one abstract method and serves as the target for lambda expressions.

@FunctionalInterface
interface Calculator {
    int add(int a, int b);
}

Calculator calculator = (a, b) -> a + b;
System.out.println(calculator.add(10, 20));

Common built-in functional interfaces include:

- Predicate
- Function
- Consumer
- Supplier
- UnaryOperator
- BinaryOperator

Method References

Method references provide a shorter syntax for calling existing methods.

Before

names.forEach(name -> System.out.println(name));

After

names.forEach(System.out::println);

Types of method references:

- Class::staticMethod
- object::instanceMethod
- Class::instanceMethod
- Class::new

Streams API

The Streams API enables functional-style operations on collections without modifying the original data.

Before Java 8

List<String> result = new ArrayList<>();

for (String name : names) {
    if (name.startsWith("A")) {
        result.add(name.toUpperCase());
    }
}

Java 8

List<String> result =
        names.stream()
             .filter(name -> name.startsWith("A"))
             .map(String::toUpperCase)
             .toList();

Common Stream operations:

- filter()
- map()
- flatMap()
- sorted()
- distinct()
- limit()
- skip()
- peek()
- reduce()
- collect()

Collectors

Collectors transform stream results into different data structures or perform aggregation.

List<String> list =
        names.stream().collect(Collectors.toList());

Map<String, Integer> map =
        students.stream().collect(Collectors.toMap(tudent::getName, Student::getAge));

Useful collectors:

- toList()
- toSet()
- toMap()
- groupingBy()
- partitioningBy()
- joining()
- counting()
- mapping()

Optional

Optional helps avoid NullPointerException by explicitly representing the presence or absence of a value.

Before Java 8

if (user != null) {
    System.out.println(user.getName());
}

Java 8

Optional.ofNullable(user)
        .map(User::getName)
        .ifPresent(System.out::println);

If the input is non-null, it returns an Optional containing the value; if the input is null, it gracefully returns an empty Optional (acting like Optional.empty()) instead of throwing a NullPointerException.

Common methods:

- of()
- ofNullable()
- empty()
- isPresent()
- ifPresent()
- orElse()
- orElseGet()
- orElseThrow()
- map()
- filter()

Tip: Avoid using Optional as an entity field, method parameter, or collection element. It is primarily intended for return types.

Default Methods

Interfaces can now provide default implementations without breaking existing implementations.

interface Vehicle {
    default void start() {
        System.out.println("Starting...");
    }
}

This allows new methods to be added to interfaces while maintaining backward compatibility.

Static Methods in Interfaces

Interfaces can also define static utility methods.

interface MathUtil {
    static int square(int n) {
        return n * n;
    }
}
System.out.println(MathUtil.square(5));

CompletableFuture

CompletableFuture simplifies asynchronous programming and supports chaining multiple asynchronous tasks.

CompletableFuture
        .supplyAsync(() -> "Hello")
        .thenApply(String::toUpperCase)
        .thenAccept(System.out::println);

Common methods:

- supplyAsync()
- runAsync()
- thenApply()
- thenAccept()
- thenCompose()
- thenCombine()
- exceptionally()
- join()
- allOf()
- anyOf()

Date & Time API

Java 8 introduced the java.time package, replacing the old Date and Calendar APIs.

Before Java 8

Date date = new Date();

Java 8

LocalDate today = LocalDate.now();
LocalDateTime now = LocalDateTime.now();
LocalTime time = LocalTime.now();

Common classes:

- LocalDate
- LocalTime
- LocalDateTime
- Instant
- Duration
- Period
- ZoneId
- DateTimeFormatter

Base64 API

Java 8 added built-in support for Base64 encoding and decoding.

String encoded = Base64.getEncoder()
              .encodeToString("Hello".getBytes());

String decoded = new String(Base64.getDecoder()
                      .decode(encoded));

Repeatable Annotations

The same annotation can now be applied multiple times.

@Role("ADMIN")
@Role("USER")
public class Employee {
}

Type Annotations

Annotations can now be applied to any use of a type.

List<@NonNull String> names;

This feature is mainly used by static analysis and validation tools.

Java 11 (LTS)

Java 11 is the second Long-Term Support (LTS) release and focuses on improving developer productivity, standardizing APIs, and enhancing JVM performance.

It introduced the modern HTTP Client, several useful String and Files APIs, and important JVM improvements like ZGC and Java Flight Recorder.

HTTP Client API

Java 11 introduced a modern HTTP client that replaces the older HttpURLConnection API. It supports both synchronous and asynchronous HTTP requests and provides a much cleaner API.

Before Java 11

URL url = new URL("https://example.com");

HttpURLConnection connection =
        (HttpURLConnection) url.openConnection();

connection.setRequestMethod("GET");

Java 11

HttpClient client = HttpClient.newHttpClient();

HttpRequest request =
        HttpRequest.newBuilder()
                   .uri(URI.create("https://example.com"))
                   .build();

HttpResponse<String> response =
        client.send(
                request,
                HttpResponse.BodyHandlers.ofString());

System.out.println(response.body());

String API Enhancements

Java 11 added several useful methods to the String class.

String text = "  Hello Java  ";

text.isBlank();
text.strip();
text.stripLeading();
text.stripTrailing();
text.repeat(3);
text.lines();

Files API Enhancements

Reading and writing files became much simpler.

Before Java 11

List<String> lines = Files.readAllLines(path);

Java 11

String text = Files.readString(path);

Files.writeString(
        path,
        "Hello Java");

Collection.toArray()

Collections can now convert directly using constructor references.

Before Java 11

String[] array = list.toArray(new String[0]);

Java 11

String[] array = list.toArray(String[]::new);

Optional Enhancements

Several new methods were added to make Optional easier to use.

Optional<String> value = Optional.of("Java");

value.ifPresentOrElse(
        System.out::println,
        () -> System.out.println("Empty"));

Useful additions:

- isEmpty()
- ifPresentOrElse()
- or()

Running Java Without Compilation

Small programs can now be executed directly without explicitly compiling them.

Before Java 11

javac Hello.java
java Hello

Java 11

java Hello.java

This is especially useful for scripts, demos, and quick experiments.

Z Garbage Collector (ZGC)

Java 11 introduced ZGC, a low-latency garbage collector designed for applications with very large heaps.

Key benefits:
- Low pause times (typically less than 10 ms)
- Handles multi-terabyte heaps
- Suitable for large enterprise systems

Java Flight Recorder (JFR)

Java Flight Recorder became available without requiring a commercial license. It helps diagnose:

- Memory issues
- CPU bottlenecks
- Thread contention
- Garbage Collection behavior
- Performance problems

JFR is widely used for production monitoring and performance tuning.

Removed Java EE Modules

Several Java EE and CORBA modules were removed from the JDK.

Examples include:
- JAXB
- JAX-WS
- CORBA
- Activation

Applications depending on these modules must now include them as external dependencies.

Java 17 (LTS)

Java 17 is the third Long-Term Support (LTS) release and introduced several language enhancements that improve readability, reduce boilerplate code, and make object-oriented programming more expressive.

Key additions include Records, Sealed Classes, Pattern Matching, and Text Blocks.

Records

Records provide a concise way to create immutable data classes. The compiler automatically generates constructors, getters, equals(), hashCode(), and toString().

Before Java 17

public class User {

    private final String name;
    private final int age;

    public User(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    @Override
    public boolean equals(Object o) {
        // omitted
    }

    @Override
    public int hashCode() {
        // omitted
    }

    @Override
    public String toString() {
        // omitted
    }
}

Java 17

public record User(
        String name,
        int age) {
}

Records are ideal for DTOs, API requests/responses, configuration objects, and immutable models.

Sealed Classes

Sealed classes restrict which classes can extend or implement them, giving developers more control over inheritance.

Before Java 17

class Shape {
}

Any class could extend Shape.

Java 17

public sealed class Shape permits Circle, Rectangle {
}
public final class Circle
        extends Shape {
}
public final class Rectangle
        extends Shape {
}

Every permitted subclass must explicitly state how it continues the boundary using exactly one of three modifiers:

1. final: The subclass is fully closed and cannot be extended further.

public final class Car extends Vehicle {
}

2. sealed: The subclass is also sealed but defines its own limited subset of children.

public sealed class Truck
        extends Vehicle
        permits SemiTruck, PickupTruck {
}

public final class SemiTruck
        extends Truck {
}

public final class PickupTruck
        extends Truck {
}

3. non-sealed: The subclass breaks the sealing chain and re-opens itself to traditional open inheritance.

public non-sealed class Bicycle extends Vehicle {
}

Pattern Matching for instanceof

Pattern matching removes the need for explicit casting after an instanceof check.

Before Java 17

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

Java 17

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

The variable str is automatically cast if the condition is true.

Text Blocks

Text Blocks simplify writing multi-line strings without excessive concatenation or escape characters.

Before Java 17

String json =
"{\n" +
"  \"name\": \"John\",\n" +
"  \"age\": 30\n" +
"}";

Java 17

String json = """
{
  "name": "John",
  "age": 30
}
""";

Commonly used for:

- SQL Queries
- JSON
- XML
- HTML
- Multi-line messages

Helpful NullPointerException

Java 17 provides more descriptive NullPointerException messages, making debugging much easier.

Before

NullPointerException

Java 17

Cannot invoke "Address.getCity()" because "user.getAddress()" is null

No code changes are required; the JVM generates the detailed message automatically.

RandomGenerator API

Java 17 introduced the RandomGenerator interface, providing a common API for different random number generators.

RandomGenerator random = RandomGenerator.getDefault();
System.out.println(random.nextInt(100));

It offers better flexibility than directly using Random.

Strong Encapsulation

Java 17 strongly encapsulates JDK internals, preventing applications from accessing internal APIs unless explicitly allowed.

This improves:

- Security
- Maintainability
- Future compatibility

Applications relying on internal JDK classes should migrate to supported public APIs.

Java 21 (LTS)

Java 21 is the fourth Long-Term Support (LTS) release and introduces significant improvements in concurrency, pattern matching, and collection APIs.

The standout feature is Virtual Threads, which enables applications to handle millions of concurrent tasks with minimal resource usage.

Virtual Threads

Virtual Threads are lightweight threads managed by the JVM instead of the operating system. They make it possible to create millions of concurrent tasks without the overhead of platform threads.

Before Java 21

ExecutorService executor = Executors.newFixedThreadPool(10);
executor.submit(() -> {
    System.out.println("Task");
});
executor.shutdown();

Java 21

try (ExecutorService executor =
         Executors.newVirtualThreadPerTaskExecutor()) {

    executor.submit(() -> {
        System.out.println("Task");
    });
}

Virtual Threads are ideal for I/O-bound applications such as web servers, REST APIs, database access, and microservices.

Tip: Virtual Threads improve scalability for blocking I/O but do not make CPU-intensive tasks faster.

Pattern Matching for switch

Switch statements can now match object types directly, making complex conditional logic cleaner and easier to read.

Before Java 21

if (obj instanceof String) {
    System.out.println(((String) obj).toUpperCase());

} else if (obj instanceof Integer) {
    System.out.println((Integer) obj * 2);
}

Java 21

switch (obj) {
    case String s ->
            System.out.println(s.toUpperCase());

    case Integer i ->
            System.out.println(i * 2);

    default ->
            System.out.println("Unknown");
}

Record Patterns

Record Patterns allow records to be deconstructed directly into their components.

public record User(
        String name,
        int age) {
}

Object obj = new User("John", 30);

if (obj instanceof User(String name, int age)) {
    System.out.println(name);
    System.out.println(age);
}

This removes the need to call individual accessor methods.

Sequenced Collections

Java 21 introduced the SequencedCollection, SequencedSet, and SequencedMap interfaces, providing a consistent way to access the first and last elements of ordered collections.

List<String> names =
        new ArrayList<>(List.of("A", "B", "C"));

System.out.println(names.getFirst());
System.out.println(names.getLast());

Useful methods include:

- getFirst()
- getLast()
- removeFirst()
- removeLast()
- reversed()

Java 25 (LTS)

Java 25 is the latest Long-Term Support (LTS) release, focusing on performance, stability, security, and developer productivity.

Unlike Java 8 or Java 21, it does not introduce many revolutionary language features.

Instead, it builds upon recent releases by finalizing preview features, improving the JVM, enhancing garbage collection, and delivering better overall performance for modern enterprise applications.

Primitive Types in Pattern Matching

Pattern matching has been extended to support primitive types, making switch statements more expressive.

Before Java 25

int number = 10;

switch (number) {
    case 1:
        System.out.println("One");
        break;

    default:
        System.out.println("Other");
}

Java 25

switch (number) {
    case int i when i > 0 ->
            System.out.println("Positive");

    case int i when i < 0 ->
            System.out.println("Negative");

    default ->
            System.out.println("Zero");
}

Scoped Values (Final)

Scoped Values provide a safer and more efficient alternative to ThreadLocal, especially when working with Virtual Threads.

static final ScopedValue<String> USER = ScopedValue.newInstance();

ScopedValue.runWhere(
        USER,
        "John",
        () -> System.out.println(USER.get()));

Unlike ThreadLocal, Scoped Values are immutable and automatically cleaned up after execution.

Structured Concurrency

Structured Concurrency simplifies coordinating multiple concurrent tasks by treating them as a single unit of work.

try (var scope = new StructuredTaskScope.ShutdownOnFailure()) {
    var user = scope.fork(() -> loadUser());
    var orders = scope.fork(() -> loadOrders());

    scope.join();
    System.out.println(user.resultNow());
}

This improves cancellation, exception handling, and resource management.

Java LTS Evolution Summary

Java Version	Major Features
Java 8	Lambda Expressions, Streams API, Functional Interfaces, Method References, Optional, CompletableFuture, Date & Time API
Java 11	HTTP Client API, String APIs, Files API, Optional Enhancements, Z Garbage Collector (ZGC), Java Flight Recorder (JFR)
Java 17	Records, Sealed Classes, Pattern Matching for `instanceof`, Text Blocks, Helpful NullPointerExceptions
Java 21	Virtual Threads, Record Patterns, Pattern Matching for `switch`, Sequenced Collections
Java 25	Scoped Values, Structured Concurrency, Primitive Pattern Matching, JVM & Garbage Collection Improvements

Conclusion

Modern Java has evolved far beyond the Java 8 era, introducing features that make applications more concise, expressive, scalable, and performant.

Whether you're writing cleaner code with Records, simplifying asynchronous programming with Virtual Threads, or leveraging Pattern Matching to reduce boilerplate, these LTS releases provide significant improvements for everyday development.

Everything New from Java 8 to Java 25 (LTS Releases)

Java 8 (LTS)

Lambda Expressions

Before Java 8

Java 8

Functional Interfaces

Method References

Before

After

Streams API

Before Java 8

Java 8

Collectors

Optional

Before Java 8

Java 8

Default Methods

Static Methods in Interfaces

CompletableFuture

Date & Time API

Before Java 8

Java 8

Base64 API

Repeatable Annotations

Type Annotations

Java 11 (LTS)

HTTP Client API

Before Java 11

Java 11

String API Enhancements

Files API Enhancements

Before Java 11

Java 11

Collection.toArray()

Before Java 11

Java 11

Optional Enhancements

Running Java Without Compilation

Before Java 11

Java 11

Z Garbage Collector (ZGC)

Java Flight Recorder (JFR)

Removed Java EE Modules

Java 17 (LTS)

Records

Before Java 17

Java 17

Sealed Classes

Before Java 17

Java 17

Pattern Matching for instanceof

Before Java 17

Java 17

Text Blocks

Before Java 17

Java 17

Helpful NullPointerException

Before

Java 17

RandomGenerator API

Strong Encapsulation

Java 21 (LTS)

Virtual Threads

Before Java 21

Java 21

Pattern Matching for switch

Before Java 21

Java 21

Record Patterns

Sequenced Collections

Java 25 (LTS)

Primitive Types in Pattern Matching

Before Java 25

Java 25

Scoped Values (Final)

Structured Concurrency

Java LTS Evolution Summary

Conclusion

Nagesh Chauhan

Share this Article