Java-Programmierung ändert sich von Java SE zu Java SE 23

Java has gone through many versions and updates since its initial release in 1996. Each version has introduced new features and enhancements, making it a robust and versatile programming language. In this article, we will go through the Java SE versions and see some examples of the features they introduced.

Java SE 1.0 (1996)
This was the first official release of Java, and it introduced the basic elements of the language, including the core APIs, JVM, and the basic tools. Let's look at an example of a "Hello World" program in Java.

// HelloWorld.java

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello World!");
    }
}

Java SE 1.1 (1997)
This version introduced support for inner classes, which are classes defined within another class. Let's see an example of an inner class in Java.

// OuterClass.java

public class OuterClass {
    private String message = "Hello";

    public void printMessage() {
        InnerClass inner = new InnerClass();
        inner.sayMessage();
    }

    private class InnerClass {
        public void sayMessage() {
            System.out.println(message);
        }
    }
}

Java SE 1.1 also introduced the JavaBeans component architecture, which allows for reusable software components. Here's a simple example of a bean in Java.

// PersonBean.java

public class PersonBean {
    private String name;
    private int age;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

Java SE 1.2 (1998)
This version introduced significant changes and additions to the language. The most notable ones are:

• Collections Framework: This new set of data structures, such as List, Set, Map, etc., made it easier to manage and manipulate collections of data.

// ListExample.java

import java.util.ArrayList;
import java.util.List;

public class ListExample {
    public static void main(String[] args) {
        List names = new ArrayList();
        names.add("John");
        names.add("Mary");
        names.add("David");

        for (String name : names) {
            System.out.println(name);
        }
    }
}

• Swing: The introduction of the Swing graphical user interface (GUI) components made it easier to create user interfaces in Java.

// HelloGUI.java

import javax.swing.*;

public class HelloGUI {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Hello World");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JLabel label = new JLabel("Hello World");
        frame.getContentPane().add(label);

        frame.pack();
        frame.setVisible(true);
    }
}

Java SE 1.2 also included a Just-In-Time (JIT) compiler integrated into the JVM for better performance and support for applets to run in web browsers through the Java Plug-in.

Java SE 1.3 (2000)
This version introduced the HotSpot JVM as the default virtual machine, improving performance. It also added the Java Sound API for handling audio, and the ability for RMI to communicate with CORBA-compliant systems.

// SoundExample.java

import javax.sound.sampled.*;

public class SoundExample {
    public static void main(String[] args) {
        try {
            Clip clip = AudioSystem.getClip();
            AudioInputStream inputStream = AudioSystem.getAudioInputStream(
                SoundExample.class.getResource("sound.wav"));
            clip.open(inputStream);
            clip.start();
        } catch (Exception e) {
            System.err.println(e.getMessage());
        }
    }
}

Java SE 1.4 (2002)
This version introduced several new features, such as:

• Assertions: Support for assertions was added, providing a useful debugging tool.

// DivideByZero.java

public class DivideByZero {
    public static void main(String[] args) {
        int a = 10;
        int b = 0;

        assert b != 0 : "Division by zero!";
        System.out.println(a / b);
    }
}

• NIO (New I/O): This enhanced input/output API introduced non-blocking I/O capabilities, making it possible to handle multiple I/O operations simultaneously.

// CopyFile.java

import java.io.*;
import java.nio.channels.*;

public class CopyFile {
    public static void main(String[] args) {
        File source = new File("source.txt");
        File target = new File("target.txt");

        try {
            FileChannel sourceChannel = new FileInputStream(source).getChannel();
            FileChannel targetChannel = new FileOutputStream(target).getChannel();
            targetChannel.transferFrom(sourceChannel, 0, sourceChannel.size());
            sourceChannel.close();
            targetChannel.close();
        } catch (IOException e) {
            System.err.println(e.getMessage());
        }
    }
}

• Regular Expressions: Built-in support for regular expressions made it easier to manipulate and search for patterns in a string.

// RegexExample.java

import java.util.regex.*;

public class RegexExample {
    public static void main(String[] args) {
        String text = "The quick brown fox jumps over the lazy dog.";
        Pattern pattern = Pattern.compile("\\b\\w{5}\\b");
        Matcher matcher = pattern.matcher(text);

        while (matcher.find()) {
            System.out.println(matcher.group());
        }
    }
}

• Logging API: This new API allowed for easier and more detailed logging of information.

// LoggerExample.java

import java.util.logging.*;

public class LoggerExample {
    private static final Logger logger = Logger.getLogger(LoggerExample.class.getName());

    public static void main(String[] args) {
        logger.log(Level.INFO, "This is an info message");
        logger.log(Level.WARNING, "This is a warning message");
        logger.log(Level.SEVERE, "This is a severe message");
    }
}

• XML Parsing: The inclusion of APIs for processing XML (SAX, DOM) made it easier to handle and manipulate XML data.

Java SE 5.0 (2004)
This version brought significant changes to the language and introduced many new features, such as:

• Generics: The introduction of generic types improved type safety and made code more concise.

// ListExample.java

import java.util.ArrayList;
import java.util.List;

public class ListExample {
    public static void main(String[] args) {
        List<String> names = new ArrayList<>();
        names.add("John");
        names.add("Mary");
        names.add("David");

        // Variable names does not have to be cast to String
        for (String name : names) {
            System.out.println(name);
        }
    }
}

• Annotations: Metadata annotations were introduced, providing a way to add extra information to code for compile-time or runtime processing.

// ExampleAnnotation.java

import java.lang.annotation.*;

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExampleAnnotation {
    String value();
}

// AnnotationExample.java

public class AnnotationExample {
    @ExampleAnnotation("Test")
    public void testMethod() {
        System.out.println("This is a test method.");
    }
}

• Enhanced for-loop: A new syntax for iterating over collections (for-each loop) was introduced.

// ListExample.java

import java.util.ArrayList;
import java.util.List;

public class ListExample {
    public static void main(String[] args) {
        List<String> names = new ArrayList<>();
        names.add("John");
        names.add("Mary");
        names.add("David");

        // Variable name does not have to be created outside of the loop
        for (String name : names) {
            System.out.println("Hello, " + name);
        }
    }
}

• Autoboxing/Unboxing: Automatic conversion between primitive types and their wrapper classes made it easier to work with different data types.

// AutoboxingExample.java

import java.util.*;

public class AutoboxingExample {
    public static void main(String[] args) {
        List<Integer> numbers = new ArrayList<>();
        numbers.add(10); // autoboxing
        numbers.add(20); // autoboxing
        numbers.add(30); // autoboxing

        int sum = 0;

        for (int num : numbers) {
            sum += num; // unboxing
        }

        System.out.println("Sum: " + sum);
    }
}

• Enumerations: The enum type was introduced, providing a built-in class for creating enums.

// DaysOfWeek.java

public enum DaysOfWeek {
    MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY
}

• Concurrency Utilities: A new API for managing threads and synchronization made it easier to develop multithreaded applications.

// BankAccount.java

import java.util.concurrent.locks.*;

public class BankAccount {
    private double balance;
    private final Lock lock = new ReentrantLock();

    public BankAccount(double balance) {
        this.balance = balance;
    }

    public void withdraw(double amount) {
        lock.lock();
        try {
            balance -= amount;
        } finally {
            lock.unlock();
        }
    }

    public void deposit(double amount) {
        lock.lock();
        try {
            balance += amount;
        } finally {
            lock.unlock();
        }
    }

    public double getBalance() {
        lock.lock();
        try {
            return balance;
        } finally {
            lock.unlock();
        }
    }
}

Java SE 6 (2006)
Java SE 6, released in 2006, brought about several major updates and new features to the Java programming language. These included enhancements in the areas of scripting, annotations, web services, and performance.

One of the most significant updates in Java SE 6 was the inclusion of a Scripting API, which allowed for the integration of scripting languages, such as JavaScript, into Java programs. This created a more flexible and dynamic environment for developers, as they were no longer limited to just using the Java language in their programs. Here's an example of how this feature could be implemented:

import javax.script.*;

public class ScriptExample {

    public static void main(String[] args) throws ScriptException {

        //creating a scripting engine for JavaScript
        ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");

        //using the evaluate method to run a simple JavaScript code
        engine.eval("print('Hello from JavaScript!');");

    }
}

Java SE 6 also introduced the concept of Pluggable Annotations, which provided a way for developers to use custom annotations and process them at compile time. This gave more control over the behavior of their programs and made it easier to add new functionality. Here's an example of how this could be used:

import java.lang.annotation.*;

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface LogInfo {
    String value();
}

public class AnnotationExample {

    @LogInfo("This method performs a database query")
    public void performQuery() {
        //method implementation
    }

    public static void main(String[] args) {
        //processing the annotation at runtime to get the value
        LogInfo annotation = AnnotationExample.class.getMethod("performQuery").getAnnotation(LogInfo.class);
        System.out.println("Annotation value: " + annotation.value()); //output: This method performs a database query
    }
}

Another major addition in Java SE 6 was the improved support for web services, with the inclusion of JAXB and JAX-WS APIs. These APIs allowed for easier implementation of web services and improved interoperability with other systems. Here's an example of how this could be utilized:

import javax.xml.bind.*;

public class WebServiceExample {

    //creating a simple POJO class to be used with JAXB
    @XmlRootElement
    public static class User {
        private String name;
        private int age;

        //default constructor and getters/setters
    }

    public static void main(String[] args) throws JAXBException {

        //marshalling the POJO into XML using JAXB
        User user = new User();
        user.setName("John");
        user.setAge(25);
        JAXBContext context = JAXBContext.newInstance(User.class);
        Marshaller marshaller = context.createMarshaller();
        marshaller.marshal(user, System.out);

    }
}

Lastly, Java SE 6 also saw improvements in performance, with various updates to the JVM and JIT compiler. This resulted in faster execution of Java programs and enhanced overall performance. Here's an example of the impact this had on the runtime:

public class PerformanceExample {

    public static void main(String[] args) {

        //comparing the execution time of a loop with and without JIT compilation
        long startTime = System.nanoTime();
        for (int i = 0; i < 1000000; i++) {
            //code to be executed
        }
        long endTime = System.nanoTime();
        System.out.println("Time taken without JIT compilation: " + (endTime - startTime));

        startTime = System.nanoTime();
        for (int i = 0; i < 1000000; i++) {
            //same code to be executed again
        }
        endTime = System.nanoTime();
        System.out.println("Time taken with JIT compilation: " + (endTime - startTime));

    }

}

Java SE 7 (2011)
Java SE 7, also known as Java 7, was released in 2011 and introduced significant changes to the language, known as Project Coin. These changes included small language enhancements that aimed to make Java code more concise and easier to read. Let's explore some of the new features introduced in Java SE 7.

One of the biggest changes was the inclusion of the "diamond operator." This operator simplified the use of generics for collections, making the code cleaner and more straightforward. Here's an example of how it replaces the traditional way of creating a generic ArrayList:

// Before Java 7
List<String> list = new ArrayList<String>();

//Java 7 and later
List<String> list = new ArrayList<>();

Another useful addition was try-with-resources, which allowed developers to manage resources like files, sockets, or database connections more efficiently. This feature ensured that resources were automatically closed at the end, saving the developer from handling it manually.

try (FileReader fileReader = new FileReader("example.txt")) {
    // File reading code
} catch (IOException e) {
    // Exception handling
}

Java SE 7 also introduced the concept of multi-catch exceptions, where multiple exceptions could be caught in a single catch block. This made exception handling more efficient, especially in cases where multiple exceptions had to be handled in the same way.

try {
    // Code that may throw exceptions
} catch (IOException | InterruptedException e) {
    // Exception handling for both IOException and InterruptedException
}

Another significant addition was the NIO.2 file I/O API, which provided enhanced support for working with files and directories. It introduced the concept of file metadata, allowing developers to access information about the file, such as its size, creation date, and last modified date. NIO.2 also added support for symbolic links, making it easier to work with file paths.

Java SE 7 also brought in the Fork/Join framework, a new approach to parallel programming. This framework simplified the process of breaking down a larger task into smaller subtasks that could be executed in parallel, improving performance in multi-core systems.

Finally, Java SE 7 allowed strings to be used as arguments in switch-case statements, which was not possible before. This made the code more readable and eliminated the need for nested if-else statements in some cases.

String day = "Monday";

switch (day) {
    case "Monday":
        // Code for Monday
        break;
    case "Tuesday":
        // Code for Tuesday
        break;

}

Another significant addition was Automatic Resource Management, where resources were automatically closed at the end of a try-catch block. This made code more efficient and reduced the likelihood of resource leaks.

Java SE 8 (2014)
Java SE 8 was released in 2014 and brought with it several new features and improvements. In this article, we will explore some of the major additions to the Java programming language in this version, along with code snippets to help understand them better.

1. Lambda Expressions: Lambda expressions were introduced in Java 8 to support functional programming. This powerful feature allows us to treat functionality as a method argument, making the code more concise and readable. Let's look at an example where we use lambda expression to sort a list of strings alphabetically.

List<String> names = Arrays.asList("John", "Mary", "Alice", "Bob");

// using lambda expression to sort the list alphabetically
Collections.sort(names, (String a, String b) -> a.compareTo(b));

// printing the sorted list
for (String name : names) {
    System.out.println(name);
}

1. Stream API: The Stream API was also introduced in Java 8, providing a way to process sequences of elements in a declarative manner. This allows for easy parallelization and optimized execution. Let's consider an example where we use the Stream API to filter a list of numbers and return only the even ones.

List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);

// using Stream API to filter even numbers and store them in a new list
List<Integer> evenNumbers = numbers.stream()
                                .filter(n -> n % 2 == 0)
                                .collect(Collectors.toList());

// printing the list of even numbers
for (Integer num : evenNumbers) {
    System.out.println(num);
}

1. Optional Class: The Optional class was introduced in Java 8 to avoid NullPointerException. It is a container object that may or may not contain a non-null value. This helps in preventing unexpected null checks and makes the code more robust. Let's see an example where we use Optional to handle a possible null value in a method.

public String getCapital(String country) {
    Map<String, String> capitals = new HashMap<>();
    capitals.put("USA", "Washington D.C.");
    capitals.put("UK", "London");
    capitals.put("France", "Paris");

    // using Optional to handle possible null value
    Optional<String> capital = Optional.ofNullable(capitals.get(country));

    return capital.orElse("Capital not available.");
}

// calling the method with a country that has a capital
System.out.println(getCapital("UK")); // output: London

// calling the method with a country that doesn't have a capital
System.out.println(getCapital("Germany")); // output: Capital not available.

1. Default Methods: Starting from Java 8, interfaces can have default method implementations. This allows us to add new functionality to existing interfaces without breaking the implementing classes. Let's look at an example where we have an interface with a default method that prints a simple message.

interface Animal {
    void makeSound();

    // default method
    default void eat() {
        System.out.println("Animal is eating.");
    }
}

// implementing the interface and overriding makeSound()
class Cat implements Animal {
    @Override
    public void makeSound() {
        System.out.println("Meow");
    }
}

// creating an instance of Cat and calling the default method
Cat cat = new Cat();
cat.eat(); // output: Animal is eating.

1. Date and Time API: Prior to Java 8, handling date and time in Java was cumbersome and not very intuitive. The Date and Calendar classes were not very developer-friendly. In Java 8, a new and comprehensive API for date and time management was introduced, known as the Date-Time API. Let's see an example where we use this API to get the current date and time.

// getting current date and time
LocalDateTime now = LocalDateTime.now();

// formatting the date and time
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd/MM/yyyy HH:mm:ss");
String formattedDateTime = now.format(formatter);

// printing the current date and time
System.out.println("Current Date and Time: " + formattedDateTime);

1. Nashorn JavaScript Engine: Nashorn JavaScript Engine was introduced in Java 8, replacing the old Rhino engine for JavaScript integration. It is a lightweight yet powerful engine that allows for seamless communication between Java and JavaScript. Let's see an example where we use Nashorn to evaluate a simple JavaScript expression.

ScriptEngineManager engineManager = new ScriptEngineManager();
ScriptEngine engine = engineManager.getEngineByName("nashorn");

// evaluating a JavaScript expression
Object result = engine.eval("2 + 2");

// printing the result
System.out.println("Result: " + result); // output: 4

Java SE 9 (2017)
Java SE 9, also known as Java 9, was released in 2017 with several major updates and new features. One of the most significant updates was the introduction of the Modular System, also known as Project Jigsaw. This feature allowed developers to create more modular Java applications, making it easier to develop and deploy them.

Here are some examples of how the Modular System works:

1. Modularity in Development: The module system allows developers to break down their application into smaller, self-contained modules, making it easier to manage and maintain. For example, a banking application can be divided into modules for user authentication, transaction processing, and account management.

2. Modularity in Deployment: With the module system, applications can be deployed in a more granular and efficient manner. Instead of deploying the entire application, only the necessary modules can be deployed, saving time and resources. This also makes it easier to update and maintain different modules separately.

Another significant feature introduced in Java 9 was JShell, an interactive tool that allows developers to write and execute Java code on-the-fly, without the need for creating a project or a file. This makes it ideal for testing out small code snippets and experimenting with new features. Here's an example of how JShell works:

// Adding two numbers in JShell

jshell> int a = 5;
a ==> 5

jshell> int b = 8;
b ==> 8

jshell> int sum = a + b;
sum ==> 13

In Java 9, a new set of factory methods were added to the Collection interface, making it easier to create immutable lists, sets, and maps. These methods use the of() static method and take in varargs parameters, making it more concise and readable. Here's an example of how these factory methods work:

// Creating an immutable list using the factory method

List<String> fruits = List.of("Apple", "Banana", "Orange");

The Process API was also enhanced in Java 9, providing more control and information about system processes. This includes the ability to get the PID (process identifier) of a running process and more efficient handling of process streams. Here's an example of how the new Process API can be used:

// Running a system process and getting the PID

Process process = new ProcessBuilder("notepad.exe").start();

long pid = process.getPid();
System.out.println("The PID of the process is: " + pid);

Lastly, Java 9 introduced a new feature called "Private Interface Methods." This allowed interfaces to have private methods, which are only accessible within the interface itself. Here's an example of how private interface methods work:

// Defining a private interface method

interface Shape {
  default double getArea() {
    return calculateArea();
  }

  private double calculateArea() {
    // private method implementation
  }
}

Java SE 10 (2018)
Java SE 10, released in 2018, brought several new features and enhancements to the language. In this article, we will explore three major changes introduced in this version - Local Variable Type Inference, G1 Garbage Collector Enhancements, and Time-Based Release Model.

Local Variable Type Inference is a feature that allows developers to declare local variables without explicitly specifying the type. This is done by using the new keyword, "var". Let's take a look at an example:

Before Java SE 10:

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

With Local Variable Type Inference:

var names = new ArrayList<String>();

As you can see, we no longer need to specify the variable type when declaring a list. The compiler can infer it from the right side of the expression.

Next, we have the G1 Garbage Collector Enhancements. This feature has improved garbage collection performance, making it more efficient and faster. The G1 garbage collector now prioritizes certain regions for cleaning, reducing the overall cleaning time and improving the overall performance of the application.

Lastly, Java SE 10 introduced a Time-Based Release Model. This change shifted the release cycle of Java to a predictable, time-based cycle every six months. This means that developers can expect a new version of Java to be released every six months, making it easier to plan and adapt to new updates and features.

Java SE 11 (2018)
Java SE 11, also known as Java 11, is a major release of the Java platform released in September 2018. This version is significant as it is designated as a LTS (Long-Term Support) release, meaning it will be supported for a longer period of time compared to non-LTS releases.

One of the major features introduced in Java 11 is the new HTTP client API, which was designed to replace the legacy HttpURLConnection. This new API provides a more modern and flexible way of performing HTTP requests, making it easier for developers to handle communication with web servers. Here's an example of how the new HTTP client API can be used to make a GET request to a URL and receive the response:

//Creating an HttpClient object
HttpClient httpClient = HttpClient.newHttpClient();

//Creating a GET request with a specified URL
HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create("https://example.com"))
            .GET()
            .build();

//Sending the request and receiving the response asynchronously
httpClient.sendAsync(request, HttpResponse.BodyHandlers.ofString())
    .thenApply(HttpResponse::body)
    .thenAccept(System.out::println);

Another significant update in Java 11 is the extended use of the var keyword in lambda expressions. Previously, the var keyword can only be used to declare local variables, but with Java 11, it can now be used to declare lambda parameters as well. This simplifies the code and improves readability, as shown in the following example:

//Before Java 11
List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5);
numbers.forEach((Integer num) -> System.out.println(num));

//With Java 11
List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5);
numbers.forEach((var num) -> System.out.println(num));

Java 11 has also removed several modules from the standard distribution, including Java EE and CORBA. This means that these modules are no longer included in the JDK and will need to be obtained separately.

Another feature introduced in Java 11 is nest-based access control. This simplifies access control between nested classes by allowing them to access each other's private members without the use of reflection. Here's an example of how nesting classes can be used with the new nest-based access control:

public class OuterClass {
    private String outerPrivateField;

    public class InnerClass {
        private String innerPrivateField;

        public void accessPrivateFields() {
            System.out.println(outerPrivateField);
            System.out.println(innerPrivateField);
        }
    }
}

Java SE 12 (2019)
Java SE 12, released in 2019, brought several exciting new features to the language. Two notable enhancements include the introduction of switch expressions and the JVM Constants API.

Switch expressions allow switch statements to be used as expressions rather than just as a control flow structure. This means that the result of a switch statement can now be assigned to a variable or used as an input to another statement. This can greatly improve the readability and conciseness of code, especially in situations where multiple switch cases are being checked for a single expression. Here is an example of a traditional switch statement versus a switch expression in Java SE 12:

Traditional switch statement:

int num = 3;
String result;
switch (num) {
    case 1: result = "One";
        break;
    case 2: result = "Two";
        break;
    case 3: result = "Three";
        break;
    default: result = "Other";
}

Switch expression:

int num = 3;
String result = switch(num) {
        case 1 -> "One";
        case 2 -> "Two";
        case 3 -> "Three";
        default -> "Other";
    };

As you can see, the switch expression is more concise and easier to read, making it a valuable addition to the language.

The JVM Constants API, or Java Virtual Machine Constants API, simplifies the process of describing class-file and runtime artifacts. This makes it easier for developers to access and use these artifacts in their code. Here is an example of how the JVM Constants API can be used to access the number of methods in a class:

Class<?> clazz = MyClass.class;
int methodCount = clazz.getMethods().length; // Using traditional method
int methodCount = clazz.constantPool().getMethodCount(); // Using JVM Constants API

Text Blocks, also known as Multi-line string literals, is a new feature introduced in Java SE 13 (2019) that simplifies the creation of strings with multiple lines. It is a welcome addition for developers who have struggled with formatting long strings in Java code.

To understand the benefits of this feature, let's look at an example. Before the introduction of Text Blocks, if we wanted to create a string with multiple lines, we would have to use the escape character "\n" to indicate where each line ends:

String oldWay = "This is a long string\nthat spans multiple lines\nin Java code";

This resulted in code that was difficult to read and maintain, especially if the string contained complex formatting or special characters.

With Text Blocks, we can now create multi-line strings without using escape characters. We simply enclose the string between three double quotes (""") and indent the lines as we want them to appear:

String newWay = """
                This is a long string
                that spans multiple lines
                in Java code
                """;

This not only makes the code more readable, but it also saves us from having to manually add escape characters and worry about formatting issues. Additionally, Text Blocks automatically remove any leading or trailing white space, so our string will be exactly as we intended it to be.

Another feature of Java SE 13 is Dynamic CDS Archives, which helps to reduce startup time and footprint through Class Data Sharing. This feature builds on the existing CDS feature, which allows classes to be shared between different Java applications to improve performance.

Dynamic CDS Archives take this a step further by allowing classes to be shared at runtime, rather than requiring them to be preprocessed and stored in a static archive. This means that classes can be loaded faster and with a smaller memory footprint, resulting in improved performance for Java applications.

Java SE 13 (2019)
Java SE 13, released in September 2019, brings with it some exciting new features that make coding in Java even easier and more efficient. One of the most notable additions is the introduction of text blocks, also known as multi-line string literals. This feature simplifies the creation of strings with multiple lines, making it easier to write and understand code.

Another feature introduced in Java SE 13 is dynamic CDS (Class Data Sharing) archives. CDS archives, introduced in Java SE 5, help to reduce startup time and memory footprint by preloading certain classes and data structures into the JVM. However, in previous versions, these archives had to be manually generated and configured.

With dynamic CDS archives, this process is now automated, making it much easier to take advantage of this optimization. Java SE 13 will automatically create and use CDS archives without any additional configuration required.

These two features, along with other enhancements and bug fixes, make Java SE 13 a valuable update for Java developers. By simplifying string creation and optimizing memory usage, this release aims to make coding in Java even more efficient and enjoyable.

Java SE 14 (2020)

Java SE 14, the latest version of Java, brought several new features and improvements to the programming language. These include finalized switch expressions, a preview of records, and a preview of pattern matching for instanceof.

One of the major changes in this release is the finalization of switch expressions. This feature was initially introduced as a preview in Java 12, and it has now been officially standardized. Switch expressions allow for a more concise and readable way to write switch statements, making them easier to maintain and understand. Here's an example of a switch statement written using the traditional syntax:

int day = 4;
String dayOfWeek = "";

switch (day) {
    case 1:
        dayOfWeek = "Monday";
        break;
    case 2:
        dayOfWeek = "Tuesday";
        break;
    case 3:
        dayOfWeek = "Wednesday";
        break;
    case 4:
        dayOfWeek = "Thursday";
        break;
    case 5:
        dayOfWeek = "Friday";
        break;
    case 6:
        dayOfWeek = "Saturday";
        break;
    case 7:
        dayOfWeek = "Sunday";
        break;
    default:
        dayOfWeek = "Invalid Day";
}

And here's an example of the same switch statement written using switch expressions:

int day = 4;
String dayOfWeek = switch (day) {
    case 1 -> "Monday";
    case 2 -> "Tuesday";
    case 3 -> "Wednesday";
    case 4 -> "Thursday";
    case 5 -> "Friday";
    case 6 -> "Saturday";
    case 7 -> "Sunday";
    default -> "Invalid Day";
};

As you can see, switch expressions use the arrow (->) operator to map the cases to their respective values, making the code more compact and visually appealing.

Another notable feature introduced in Java SE 14 is the preview of records. Records provide a more concise syntax for declaring classes that are primarily used to store data. They reduce boilerplate code and allow developers to focus on the data itself. Here's an example of a record that represents a person's first name, last name, and age:

record Person(String firstName, String lastName, int age){};

This record is equivalent to a traditional class with private fields, a constructor, and getters and setters, but with much less code.

Finally, Java SE 14 also introduced a preview of pattern matching for instanceof. This feature simplifies the syntax for checking the type of an object and allows for more concise code. Here's an example of how pattern matching for instanceof works:

Object obj = "Hello";

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

In this example, the instanceof operator is used to check if the object obj is of type String. If it is, the variable str is automatically declared and assigned the value of obj, and the code inside the if statement is executed.

Java SE 15 (2020)
The newest edition of Java, Java SE 15 (also known as Java 15), offers several new features for coding convenience and flexibility. In this version, the most notable highlights include finalized text blocks for multi-line strings, sealed classes for restricting class extension and implementation, and hidden classes for creating classes that are not easily detectable through classpath scanning. Let's take a closer look at these three features and see how they work.

The addition of text blocks in Java 15 allows for more readable and complex string formatting. With text blocks, multi-line strings can be written without the need for escape sequences or concatenation.

Moving on to sealed classes, this feature allows for the creation of classes that can only be extended or implemented by a specific set of classes. This restricts the flexibility of other classes inheriting from it. Here's an example:

public sealed class Shape 
    permits Circle, Square, Triangle {

    // class implementation
}

In this example, the "Shape" class is sealed and can only be extended by the "Circle", "Square", and "Triangle" classes. Any other class trying to extend "Shape" will result in a compilation error. This ensures better control over class inheritance and reduces the risk of unintended consequences.

Lastly, hidden classes in Java 15 allow for classes to be created that are not easily discoverable by classpath scanning. This feature is particularly useful for creating support classes that are only used internally by other classes and do not need to be accessed externally. Here's an example:

class InternalSupportClass implements SomeInterface {

    // class implementation
}

SomeInterface hiddenClass = HiddenClassFactory.createHiddenClass(InternalSupportClass.class);

Java SE 16 (2021)
In this example, the "InternalSupportClass" is hidden from external access, and only the interface "SomeInterface" is visible. This provides an extra layer of security and organization to the code.

Java SE 16, also known as Java 16, is the latest version of the popular programming language released by Oracle Corporation in March 2021. It introduces several new features and enhancements, including finalized records, pattern matching for the instanceof operator, and the introduction of the Vector API (Incubator).

Records, also referred to as data classes, are one of the most significant additions to Java 16. They offer a simpler and more efficient way of defining classes that are primarily used for storing data. Prior to Java 16, developers had to write lengthy code to define such classes, but with records, they can be created in just a few lines of code. Let's take a look at an example:

// Defining a Record class
record Student(String name, int age) {
    // Record body
}

In the above snippet, the Student class is defined as a record, with the name and age fields being automatically declared and assigned as final variables. Records also provide a concise toString(), equals(), and hashCode() methods, making it easier to work with data objects.

Another new feature in Java 16 is the finalization of pattern matching for the instanceof operator. This feature was initially introduced in Java 14 as a preview and has now been fully implemented. Using pattern matching, developers can perform type checks and casts in a more concise and readable manner. Here's an example:

// Type check using pattern matching
if (obj instanceof Integer intObj) {
    // Use intObj as an Integer
}

In the above snippet, the obj object is checked to see if it is an instance of the Integer class, and if it is, it is automatically casted to the intObj variable, allowing for easier access and manipulation of the value.

Additionally, Java 16 introduces the Vector API (Incubator), which provides a new and efficient way of expressing vector computations. This allows for improved matrix and vector operations, which can now be compiled to optimized machine code for faster execution. Let's see an example of using the Vector API to multiply two matrices:

// Defining and multiplying two matrices using Vector API
var mat1 = FloatMatrix.ofRows(3, 2, 3, 4, 5, 6);
var mat2 = FloatMatrix.ofRows(2, 6, 7, 8, 9, 1);
var result = mat1.matmul(mat2);

In the above snippet, mat1 and mat2 are both defined as FloatMatrix objects using the ofRows() method, and the matmul() method is used to multiply and store the result in the result variable.

Java SE 17 (2021)
Java SE 17, released in 2021, is the latest version of Java offering a wide range of features and enhancements for developers. One of the major changes in this release is that it has become the next LTS (Long-Term Support) version, providing support and updates for a longer period of time.

One of the most talked-about features in Java 17 is the addition of sealed classes. A sealed class is a final class that allows developers to control its inheritance. This means that other classes cannot extend the sealed class unless they are explicitly allowed to do so. This helps in better encapsulation and prevents unexpected inheritance which can lead to security vulnerabilities or errors in the code.

Another noteworthy addition in Java 17 is the preview feature of pattern matching for switch statements. This feature expands the use of pattern matching to switch statements, allowing developers to use more concise and readable code. Let's see how this works with a simple example:

public enum Day {
  MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY
}

Day day = Day.MONDAY;

String result = switch (day) {
  case MONDAY, TUESDAY, WEDNESDAY, THURSDAY -> "Weekday";
  case FRIDAY -> "TGIF";
  case SATURDAY, SUNDAY -> "Weekend";
};
System.out.println(result); // Output: Weekday

As shown in the example, the use of pattern matching with switch statements allows for more concise code that is easier to read and understand.

The Java Foreign Function & Memory API, also known as Incubator, is another significant addition in Java 17. It allows developers to interact with non-Java code and access memory outside of the JVM heap. This feature is especially useful for integrating with existing native libraries or working with low-level system resources. Let's take a look at an example of invoking a C function in Java using this API:

public class JNITest {
  public static native int sum(int num1, int num2);

  static {
    System.loadLibrary("jniNativeLib");
  }

  public static void main(String[] args) {
    int sum = sum(10, 20);
    System.out.println("Sum of 10 and 20 is " + sum);
  }
}

The above code invokes the sum function present in a native library named jniNativeLib and prints the result, showcasing the use of Java Foreign Function & Memory API.

Java SE 18 (2022)
In the latest release of Java SE 18 in 2022, developers can now look forward to a few exciting updates and new features. Let's take a closer look at these additions.

One of the most highly anticipated updates is the introduction of a Simple Web Server, a command-line tool that allows you to easily start a minimal HTTP server. This tool is perfect for testing and debugging web applications without having to set up a server environment.

Another noteworthy update is the change to the default charset for Java APIs. Starting with Java SE 18, the default charset for all APIs will now be UTF-8. This means that all APIs will now use the UTF-8 encoding by default, instead of relying on the default system encoding. This update will help to avoid any encoding issues when working with non-ASCII characters in your applications.

Lastly, Java SE 18 also includes the second preview of Pattern Matching for Switch. This feature was first introduced in Java SE 17 and allows for more concise and readable code when working with switch statements.

These updates and features in Java SE 18 demonstrate the continual efforts to improve and enhance the Java language. Developers can look forward to incorporating these new tools and capabilities into their projects and enjoy a more efficient and pleasant development experience.

Java SE 19 (2022)
Java SE 19 is the upcoming release of the Java language and platform, scheduled for release in 2022. This release brings several new features and updates, including the highly anticipated Virtual Threads, Structured Concurrency, Record Patterns, and Pattern Matching for Switch.

The Virtual Threads feature is a preview that introduces lightweight threads to the Java platform. These threads are designed to simplify the writing of concurrent applications by providing an alternative to traditional threads. Virtual Threads are created and managed by the Java runtime, allowing for more efficient and streamlined concurrency in applications.

try (ExecutorService myExecutor = Executors.newVirtualThreadPerTaskExecutor()) {
    Future<?> future = myExecutor.submit(() -> System.out.println("Running thread"));
    future.get();
    System.out.println("Task completed");
    // ...

The Structured Concurrency feature, currently in the Incubator stage, introduces a new model for managing concurrency in multithreaded programs. With this feature, the Java runtime ensures that all concurrent tasks are executed in a structured and predictable way, preventing issues such as thread leaks or deadlocks.

The Record Patterns feature, in the preview stage, adds support for patterns in Record classes, allowing for deconstruction of records into their constituent parts. This feature simplifies the process of accessing and extracting data from records. Here is an example of using patterns on Record classes:

record Person(String name, int age) {}

// Deconstructing the Person record using pattern matching
Person person = new Person("John", 25);
String name = person.name();
int age = person.age();

Lastly, the Pattern Matching for Switch feature, currently in its third preview, introduces further refinements for pattern matching with switch statements. This feature allows for more complex and flexible pattern matching in switch statements, making code more concise and readable. Here is an example of using pattern matching in a switch statement to handle different types of objects:

Object obj = new Person("Jane", 30);

switch(obj) {
    case String name -> System.out.println("Name: " + name);
    case Person p -> System.out.println("Person: " + p.name() + ", Age: " + p.age());
    default -> throw new IllegalArgumentException("Unexpected value: " + obj);
}

In conclusion, Java SE 19 brings a variety of new features and updates that aim to enhance the development of concurrent applications and improve overall code readability. These features are currently in the preview or incubator stage, giving developers an early opportunity to try them out and provide feedback before their official release in 2022.

Java SE 20 (2023)
Two notable areas that will see significant refinements are record patterns and pattern matching for switch statements. Additionally, the foreign function and memory API will also receive a boost in its second preview.

Record patterns were first introduced in Java 14 as a new way to access and manipulate data in a concise and declarative manner. With the upcoming release of Java SE 20, record patterns will undergo continued refinement to make them even more intuitive and easy to use. Here's an example of a record pattern in action, using the new syntax for destructuring a record:

// Record class with two fields
record Book(String title, String author){}

// Destructuring the record to access its fields
Book book = new Book("Pride and Prejudice", "Jane Austen");
String author = book.author(); // Accessing field using record method
String title = book.title(); // Accessing field using record method
System.out.println("The book " + title + " was written by " + author);
// Output: The book Pride and Prejudice was written by Jane Austen

Pattern matching for switch statements, which was first introduced in Java 12, will continue to evolve in its fourth preview for Java SE 20. This feature allows developers to perform more complex conditional logic with simple and concise syntax. With each preview, new enhancements and features are added to make pattern matching even more powerful. Here's an example of how pattern matching for switch statements can be used to handle different types of exceptions:

try {
   // Code that may throw an IOException
} catch(Exception e) {
   // Matching Exception to its subtype to handle specific exception handling
   switch(e) {
      case IOException ioe -> System.out.println("Caught an IOException");
      case NoSuchElementException nsee -> System.out.println("Caught a NoSuchElementException");
      case Exception other -> System.out.println("Caught an unknown Exception");
   }
}

In addition to these language-related features, Java SE 20 will also see the second preview of the foreign function and memory API. This API allows Java developers to interact with native code and manage memory in a more efficient and seamless manner. With further enhancements, developers can expect even more capabilities and flexibility when integrating Java code with libraries written in other languages such as C or C++. Here's an example of using the foreign function and memory API to call a native function from within a Java program:

void sayHello(){ // Native function defined in C
   printf("Hello from C!");
}

public static native void sayHello(); // Java declaration of native function
public static void main(String[] args){
   Main.sayHello(); // Calling native function from Java
}

Java SE 21 (2023)
Java SE 21 will be the next major release of the popular programming language, scheduled to be released in 2023. This version will serve as the new Long Term Support (LTS) release, providing stability and support for enterprises and developers for the years to come.

One of the most anticipated features in Java SE 21 is the introduction of Virtual Threads. These are lightweight, JVM-managed threads that offer significant improvements in scalability and efficiency for high-concurrency applications. This means that applications with a large number of concurrent tasks can run more smoothly and efficiently, reducing the burden on system resources.

Let's take a look at an example of Virtual Threads in action:

// Create a virtual thread
 Thread virtualThread = Thread.startVirtualThread(() -> {
            System.out.println("Running task in a virtual thread: "
                               + Thread.currentThread().getName());
        });

        // Waiting for virtual threads to complete
        try {
            virtualThread.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

In this code snippet, we are creating a new virtual thread using the VirtualThread.start() method and defining the task to be executed using a lambda expression. This thread will run concurrently with other tasks, providing better performance and resource utilization.

Another exciting addition in Java SE 21 is Sequenced Collections. These are new interfaces that will enable developers to maintain and manipulate collections of ordered data. This will allow for more efficient sorting, searching, and filtering of data, making it easier to work with large datasets.

Let's see how Sequenced Collections can be used in code:

// Create a new list with ordered data
List<String> names = Arrays.asList("John", "Jane", "Mary", "Tom");
// Use the ordered data to create a sequence
Sequence<String> nameSequence = names.stream()
        .filter(name -> name.startsWith("J"))
        .sorted()
        .toSequence();

// Iterate over the sequence
Iterator<String> itr = nameSequence.iterator();
while (itr.hasNext()) {
    System.out.println(itr.next());
}

In this example, we are creating a sequence of names starting with the letter "J" from a list of names. This sequence can be used for various operations, such as filtering and sorting, providing a more efficient way to work with ordered data collections.

Lastly, Java SE 21 also introduces Pattern Matching for Switch, which simplifies conditional logic by extending pattern matching to switch statements. This allows for a more concise and readable code, especially when dealing with multiple cases.

Here's an example of Pattern Matching for Switch in action:

interface Account {}
record SavingAccount (double balance) implements Account {}
record CreditCardAccount(double creditLimit, double used) implements Account {}
record HomeLoanAccount(double totalAmount, double amountPaid) implements Account {}

Account account= new CreditCardAccount(10000, 1000);

switch (shape) {
  case SavingAccount s:
    System.out.println("Account Balence is " + balance);
    break;
  case CreditCardAccount c:
    System.out.println("Credit Balence is: " + (creditLimit-used));
    break;
  case HomeLoanAccount h:
    System.out.println("Balence  " +(totalAmount-amountPaid));
    break;
  default:
    System.out.println("Unknown Account");
}

In this code snippet, we are using pattern matching in a switch statement to determine the type of the obj variable and perform specific actions. This eliminates the need for numerous if-else statements, making the code more concise and readable.

In conclusion, Java SE 21 brings exciting new updates and features to the language, such as Virtual Threads, Sequenced Collections, and Pattern Matching for Switch. This release will continue to solidify Java's position as one of the most popular and reliable programming languages for years to come.

Java SE 22 (2024)
In Java SE 22 (2024), there will be several exciting new features, including the Finalization of the Foreign Function & Memory API, String Templates, and Structured Concurrency. Let's take a closer look at each of these features and how they can benefit Java developers.

The Finalization of the Foreign Function & Memory API will greatly improve the ability for Java programs to interact with native code and memory. This feature will replace the older JNI approach, making it safer and more efficient for Java developers to work with native resources.

Next up, we have String Templates, which greatly enhance string handling in Java. With String Templates, developers can easily and safely embed expressions within string literals. This eliminates the need for concatenation and makes code more readable. See an example of how String Templates can be used:

int x = 10;
int y = 20;
StringTemplate st = RAW."\{x} + \{y} = \{x + y}";
List<String> fragments = st.fragments();
List<Object> values = st.values();

Finally, the second preview of Structured Concurrency will be available in Java SE 22. This feature improves the management of concurrent tasks, making it easier for developers to write reliable and understandable code. Let's see how Structured Concurrency can be used:

    void handleShutdownOnFailure() throws ExecutionException, InterruptedException {
        try (var scope = new StructuredTaskScope.ShutdownOnFailure()) {
            // var t = new SCRandomTasks();
            var subtasks = IntStream.range(0, 5)
                                    .mapToObj(i -> scope.fork(() -> randomTask(1000, 850)))
                                    .toList();
            scope.join()
                 .throwIfFailed();
            var totalDuration = subtasks.stream()
                                        .map(t -> t.get())
                                        .reduce(0, Integer::sum);
            System.out.println("Total duration: " + totalDuration);
        }
    }

    void handleShutdownOnSuccess() throws ExecutionException, InterruptedException {
        try (var scope = new StructuredTaskScope.ShutdownOnSuccess()) {
            IntStream.range(0, 5)
                     .mapToObj(i -> scope.fork(() -> randomTask(1000, 850)))
                     .toList();
            scope.join();
            System.out.println("First task to finish: " + scope.result());
        }
    }       

In summary, these new features in Java SE 22 will greatly benefit developers by enhancing Java's capabilities in working with native code, improving string handling, and simplifying concurrent tasks. We look forward to seeing these features in action and how they will be used to create even better and more efficient Java programs.

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