Java 9, 10, 11, and Beyond

Java has continued to evolve with each version, introducing features that enhance developer productivity, code readability, and performance. The module system, JShell, local-variable type inference, HTTP client API, and numerous other features introduced in Java 9 and beyond have shaped the language to meet the demands of modern software development. Developers are encouraged to stay updated with the latest Java releases to leverage the latest capabilities and improvements in the language and runtime. Whether you are working with the module system, experimenting with JShell, or using the latest language features, Java's ongoing evolution ensures that it remains a robust and versatile platform for building a wide range of applications.

14.1 Overview of Java Versions 9, 10, 11, and Beyond

Java has been evolving over the years with the introduction of new features and enhancements in each version. Java 9, 10, 11, and subsequent releases have brought significant improvements to the language, runtime, and libraries. This chapter provides an overview of the key features introduced in Java 9 and beyond.

14.2 Java 9: Module System (Project Jigsaw)

Module System (Project Jigsaw): One of the most significant changes in Java 9 is the introduction of the module system. It allows developers to create modular applications, enhancing encapsulation and improving maintainability. Modules define a set of related packages and their dependencies, providing a more structured way to organize code.

// Example: Creating a Simple Module
module com.example.greetings {
    exports com.example.greetings;
}
    

In this example, a simple module named com.example.greetings is defined, and it exports the package com.example.greetings.

14.3 Java 9: JShell (Interactive REPL)

JShell (Interactive REPL): Java 9 introduced JShell, a Read-Eval-Print Loop (REPL) tool that allows developers to interactively evaluate Java code snippets. JShell facilitates quick experimentation and testing without the need for a full compilation cycle.

// Example: Using JShell
$ jshell
|  Welcome to JShell
|  For an introduction type: /help intro
jshell> int sum = 5 + 3;
sum ==> 8
jshell> String greeting = "Hello, JShell!";
greeting ==> "Hello, JShell!"
jshell> System.out.println(greeting);
Hello, JShell!
    

In this example, JShell is used to perform simple calculations and print a greeting message.

14.4 Java 10: Local-Variable Type Inference (var)

Local-Variable Type Inference (var): Java 10 introduced the var keyword, allowing developers to declare local variables with inferred types. This enhances code conciseness while maintaining static typing.

// Example: Using var
var number = 42;
var message = "Java 10 var";
System.out.println(number); // Output: 42
System.out.println(message); // Output: Java 10 var
    

In this example, the var keyword is used to declare variables without explicitly specifying their types.

14.5 Java 11: Local-Variable Syntax for Lambda Parameters

Local-Variable Syntax for Lambda Parameters: Java 11 introduced the ability to use the var keyword for lambda parameters. This allows more expressive and concise lambda expressions.

// Example: Using var in Lambda Parameters
// Before Java 11
List languages = Arrays.asList("Java", "Kotlin", "Scala");
languages.forEach((String language) -> System.out.println(language));

// Java 11 and later
languages.forEach((var language) -> System.out.println(language));
    

In this example, the var keyword is used for lambda parameters, making the code more concise.

14.6 Java 11: HTTP Client (Standardized)

HTTP Client (Standardized): Java 11 introduced a standardized HTTP client API (java.net.http) as an incubator module. This API provides a modern and flexible approach for interacting with HTTP services.

// Example: Using the HTTP Client
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class HttpClientExample {
    public static void main(String[] args) throws Exception {
        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
            .uri(new URI("https://jsonplaceholder.typicode.com/posts/1"))
            .GET()
            .build();
        HttpResponse response = client.send(request, HttpResponse.BodyHandlers.ofString());
        System.out.println("Response Code: " + response.statusCode());
        System.out.println("Response Body: " + response.body());
    }
}
    

In this example, the standardized HTTP client is used to make a simple GET request and print the response.

14.7 Java 11 and Beyond: LTS (Long-Term Support) Releases

Starting with Java 11, Oracle introduced a new release cadence for Java, with feature releases every six months. Additionally, every three years, a Long-Term Support (LTS) release is designated. LTS releases receive extended support and updates for a more extended period, making them suitable for applications with longer life cycles.

14.8 Java 12, 13, 14, and Beyond: Incremental Improvements

Subsequent Java releases, including Java 12, 13, 14, and beyond, have focused on incremental improvements, new features, and enhancements. Some notable features introduced in these releases include:

• Switch Expressions (Java 12): Enhanced switch statements to support both statement and expression forms.
• Text Blocks (Java 13): Simplified multiline string literals for improved readability.
• Pattern Matching (Java 16): Continued enhancements to pattern matching for improved code conciseness.

// Example: Using Text Blocks (Java 13)
String html = """

    
        
Hello, Text Blocks!
    

""";
System.out.println(html);
    

In this example, the text block feature introduced in Java 13 is used to create a multiline HTML string.

14.9 Java 17: Latest LTS Release

As of the latest developments, Java 17 is the latest LTS release, providing extended support and stability. It includes various enhancements and features, including improved pattern matching, extended support for modern hardware architectures, and updates to the standard libraries.