New Features in Java

How is Java Marching Forward? #

📌 Breaking Myth

Myth: "Java is old and unpopular"
Truth: Java remains one of the most popular programming languages worldwide!
- Java is one of the popular choices for building:
  - Modern cloud applications (Spring Boot, Quarkus, Micronaut)
- IMHO Java is evolving faster than ever, staying modern, powerful, and future-proof!

📌 Continuous Innovation in Java Eco System

Java 8 – Embraced functional programming with Lambda expressions and Streams.
Java 9 – Introduced modularization to the Java Platform - enabling faster startup and less memory footprint for Java applications
Java 10 to NOW – Started the six-month release cycle for faster updates and quick feedback.
Java 11 to NOW – Reduced code verbosity
- Switch Expressions – More concise conditional logic.
- Text Blocks – Simplifies multi-line strings.
- Records – Reduces boilerplate for data objects.
- Pattern Matching – Enhances code readability and conciseness.
Java 21 to NOW:
- Project Loom – Virtual threads for high-performance concurrency.
- Cloud & Container-Ready – Optimized for modern cloud-native applications.

What are the primary goals behind recent Java releases? #

Make it concise – Reduce boilerplate and improve readability.
- Records – No need for boilerplate code in data classes.
```
record Person(String name, int age) {}
```
- Switch Expressions – More readable and concise switch statements.
```
String result = switch (day) {
    case MONDAY, FRIDAY -> "Weekend is near!";
    default -> "Regular day.";
};
```
Cloud and container support – Improve compatibility with cloud-native environments.
- Optimized JDK Container Images – Optimized JDK images for containers with small memory footprint and fast start up times.
- GraalVM – Enables efficient native image compilation for lightweight, fast-running applications.
Improve concurrency – Introduce Virtual Threads for scalable parallelism.
- Virtual Threads – Handles millions of lightweight threads efficiently.
```
Thread.startVirtualThread(
    () -> System.out.println(
      "Hello from a virtual thread!"));
```
Developer productivity – Provide better debugging tools and runtime efficiency.
- JShell – Interactive REPL for quick testing.
```
jshell> System.out.println("Hello, Java!");
```
- Simpler Main Without Class - Write just the method, skip the boilerplate
```
//HelloWorld.java
void main() {
  System.out.println("Hello, World!");
}
```
- Easy Launch without Compilation - Run source files directly
```
$ java HelloWorld.java
```
Reduce startup time – Optimize performance for faster application launch.
Better memory management – Optimize Garbage Collection (GC) for lower latency.
Backward compatibility – Ensure smooth migration from older versions.

What are some major Java versions and their most important features? #

📌 J2SE 5.0

Enhanced For Loop – Simplifies iteration over collections and arrays.
```
for (int num : numbers) {
  //Do something
}
```
Generics – Enables type safety in collections and methods.
```
public class HashMap<K,V> extends AbstractMap<K,V>
```

Enums – Provides a type-safe way to define constants.

enum Season {
    WINTER, SPRING, SUMMER, FALL
}

Autoboxing – Automatically converts primitives to wrapper classes.
```
Integer integer = 5;
int i = integer;
```

📌 Java SE 7

Try-With-Resources: Automates resource management in try-catch blocks.

try (BufferedReader br = 
    new BufferedReader(
        new FileReader("file.txt"))) {

Strings in Switch: Allows using String values in switch statements.

switch (day) {
    case "Monday": //Do Something;
    case "Friday": //Do Something;
    case "Sunday": //Do Something;
    default: //Do Something;
}

📌 Java SE 8

Lambda Expressions – Allows writing concise, functional-style code.

public static Predicate<Course> 
        createPredicate(int cutoff) {
    return course -> 
           course.getReviewScore() > cutoff;
}

Streams API – Provides a powerful way to process collections.

List<String> transformedNumbers = numbers.stream()
            .map(x -> x * x)  // Step 1: Square each number
            .map(x -> x + 10) // Step 2: Add 10
            .map(x -> "Value: " + x) // Step 3: Convert
            .toList();    // Collect the result

Functional Programming – Introduces higher-order functions and immutability.

courses.stream()
       .sorted((c1, c2) -> c1.length() - c2.length())
       .forEach(System.out::println);

📌 Java SE 9

Modularization – Splits JDK into modules for better scalability.
JShell (REPL) – Interactive command-line tool for testing Java code.
```
jshell> System.out.println("Hello, Java!");
```

📌 Java SE 10

Local Variable Type Inference (var) – Allows type inference for local variables.

// ArrayList<String> numbers = new ArrayList<>();

// No need to repeat ArrayList<String>
var numbers = new ArrayList<String>(); 

// Inferred as HashMap<Integer, String>
var map = new HashMap<Integer, String>();

📌 Java SE 14

Switch Expressions – Enables switch to return values, reducing boilerplate code.

String result = switch (day) {
      case MONDAY, FRIDAY -> "Weekend is near!";
      default -> "Regular day.";
};

📌 Java SE 15

Text Blocks – Simplifies working with multi-line strings.

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

📌 Java SE 16

Pattern Matching for instanceof - Simplify code making use of instanceof

public void process(Object obj) {
    if (obj instanceof String s) {
        // No explicit cast needed
        System.out.println("Message: " + s);  
    }
}

Record Classes – Provides a compact syntax for immutable data objects.

public record Person(
    String name, String email, 
    String phoneNumber) {}

📌 Java SE 17

Sealed Classes - Controlled inheritance of your class hierarchies.

sealed class Vehicle permits Car, Truck, Bike {} 

// No further subclassing  
final class Car extends Vehicle {}  

// Can be extended freely  
non-sealed class Truck extends Vehicle {}

sealed class Bike extends Vehicle 
                  permits ElectricBike {}  

// No further subclassing  
final class ElectricBike extends Bike {}

📌 Java SE 21

Virtual Threads – Improves concurrency with lightweight threads.

Thread.startVirtualThread(
    () -> System.out.println(
      "Hello from a virtual thread!"));

Sequenced Collections – Adds operations for ordered collections.

interface SequencedCollection<E> extends Collection<E> {
    void addFirst(E element);  
    void addLast(E element);
    E getFirst();  
    E getLast();  
    E removeFirst();  
    E removeLast();  
    SequencedCollection<E> reversed();
}

Record Patterns - Supports deconstruction, including nested patterns

record Transaction(
    String sender, String receiver, double amount) {}

public void processTransaction(Object obj) {
    if (obj instanceof Transaction(
            String sender, String receiver, double amount)) {
        System.out.println("Processing transaction: " 
            + sender + " -> " + receiver + " : ₹" + amount);
    }
}

Pattern Matching for Switch - More expressive and type-safe switch statements

interface CustomerMessage{}
record TextMessage(String text) implements CustomerMessage {}
record Ticket(int ticketNumber) implements CustomerMessage {}

CustomerMessage message = new Ticket(1050);

String response = switch (message) {
    case TextMessage(String text) 
            -> "Processing text message: " 
                                + text;
    case Ticket(int ticketNumber) 
            -> "Processing support ticket: #" 
                                + ticketNumber;
};

System.out.println(response);

📌 Java SE 22

Unnamed Variables & Patterns – Allows ignoring unused variables in code.

switch (obj) { //I will not use the value!
    case String _ -> System.out.println("String");
    case Integer _ -> System.out.println("Integer");
    default -> System.out.println("Unknown type.");
}

📌 Java SE 23

Markdown Documentation Comments – Enhances Javadoc with Markdown support.

/// This is the **traditional** 
/// *Hello World!* program.

/// This is the <strong>traditional</strong> 
/// <em>Hello World!</em> program.

📌 Java SE 24

Stream Gatherers – Introduces new ways to aggregate stream data.

//A new way to group, 
//transform, and aggregate stream elements
List<List<Integer>> windows = numbers.stream()
            .gather(Gatherers.windowFixedSize(3))
            .toList();
//[1, 2, 3]
//[4, 5, 6]
//[7, 8, 9]
//[10]

📌 Ongoing Improvements

Performance Optimizations – Enhances start up speed, memory footprint and efficiency of Java applications.
Garbage Collection Enhancements – Improves memory management and GC algorithms.
API and Syntactic Improvements – Continuously refines Java syntax and library functions.

On this page

How is Java Marching Forward? #

What are the primary goals behind recent Java releases? #

What are some major Java versions and their most important features? #