Java Latest Version Update — Java 21

Java 21

Let us discuss about , what are the new things in the upcoming version of Java in a short passage.

Oracle Corporation releasing the new features of Java in every six month. Accordingly , JEP released some information about the Java 21 release. It is expected to releasing on September month — 2023

The JDK Enhancement Proposal (or JEP) is a process drafted by Oracle Corporation for collecting proposals for enhancements to the Java Development Kit and OpenJDK

//main method
public class HelloWorld{
  void main(){
     System.out.println("hello World..");
  }
}

//unnamed class
package demo;

void follow(){
   System.out.println("No class");
}

One of the major update of java 21 is Unnamed classes and Instance main method. Because , We’ve been struggling to understanding the java syntax , especially public static void main(String[] args) line. In the upcoming release it will be replaced as shown in the above code.

Record Patterns : can be used to simplify and improve the readability of code that works with records. For example, the following code uses a Record Pattern to match against a record that has a specific value for its x field:

record Point(int x, int y) {}

// Match against a point with x = 10
Point point = Point(10, 20);
if (point == Point(10, _)) {
  // Do something with the point
}

Pattern Matching : Pattern Matching for switch can be used to simplify and improve the readability of code that uses switch statements. For example, the following code uses Pattern Matching for switch.

static void check(Object obj) {
    String formatted = switch (obj) {
        case Integer i -> String.format("int %d", i);
        case Long l    -> String.format("long %d", l);
        case Double d  -> String.format("double %f", d);
        case String s  -> String.format("String %s", s);
        default        -> obj.toString();
    };
}

Sequenced Collections : are a new type of collection that provides direct access to the first and last elements of the collection. This can be useful for applications that need to iterate over a collection in a specific order. Sequenced Collections are implemented using a linked list data structure. This makes them efficient for iterating over a collection in a forward or backward direction.

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

    // new method
    SequencedCollection<E> reversed();
}

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

public class SequencedCollectionExample {

  public static void main(String[] args) {
    List<String> strings = new ArrayList<>();
    strings.add("Hello");
    strings.add("World");

    // Get a reversed view of the sequenced collection.
    SequencedCollection<String> reversedStrings = strings.reversed();
    for (String string : reversedStrings) {
      System.out.println(string);
    } // Prints "World" "Hello"
  }
}

String Templates : String templates are a new feature in Java 21 that allow you to interpolate expressions into string literals. This can be useful for generating dynamic text, such as error messages or personalized greetings.

The syntax for string templates is as follows:

String name="fredrick";
String text=STR. "The name is {name}.";

The name is fredrick.

The STR is the template processor, which tells the compiler that this is a string template. The dot (.) is a separator between the template processor and the template string. The template string is enclosed in double quotes. The expressions to be interpolated are enclosed in curly braces.

In this example, the expression {name} will be interpolated with the value of the name variable.

The Java platform provides two template processors:

• STR: This is the default template processor and it performs string interpolation.
• FMT: This template processor can be used to format text, such as by adding commas to numbers or converting strings to uppercase.

Java 21 is a major release that includes a number of new features and improvements. These features make Java a more powerful and versatile language for a wider range of applications.

Enhanced Features in JDK 21

1. String Templates
2. Sequenced Collections
3. Generational ZGC
4. Record Patterns
5. Pattern Matching for switch
6. Foreign Function & Memory API
7. Unnamed Patterns and Variables
8. Virtual Threads
9. Unnamed Classes and Instance Main Methods
10. Scoped Values
11. Vector API (Sixth Incubator)
12. Deprecate the Windows 32-bit x86 Port for Removal
13. Prepare to Disallow the Dynamic Loading of Agents
14. Key Encapsulation Mechanism API
15. Structured Concurrency.

You can refer all these topics in the OpenJDK Official Page,

JDK 21

If you want to understand these topics in depth , you can refer this website.

JDK 21: The new features in Java 21

click here to read the medium blogger article for practical examples,

🚀 Java 21: Unleashing Exciting Updates for All Developers! 🎉

Conclusion

JDK 21 introduces exciting new features and performance enhancements that significantly impact Java development. Embracing the latest JDK version empowers developers to leverage cutting-edge capabilities, streamline development processes, and create more robust and efficient applications.

Stay ahead of the curve by exploring JDK 21 and incorporating its new features into your Java projects. Embrace the power of enhanced Java development and unlock new possibilities for innovation and success. Happy coding with JDK 21!

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