Java New Features (Java 9 and above)

Java regularly introduces new features and enhancements in each version. This guide will highlight some of the new features introduced in Java 9 and above, providing syntax, examples, explanations, use cases, important points, and a summary of each feature.

Java 9: Module System

Java 9 introduced the module system to enhance modularity. Modules provide a way to encapsulate code, manage dependencies, and improve the maintainability of large codebases.

Syntax

module com.example.module {
    requires module1;
    requires module2;
    exports com.example.package;
}

Example

// Module-info.java file
module com.example.greetings {
    exports com.example.greetings;
}

// Greetings.java file
package com.example.greetings;

public class Greetings {
    public static String sayHello() {
        return "Hello, Java 9 Modules!";
    }
}

// Main.java file
import com.example.greetings.Greetings;

public class Main {
    public static void main(String[] args) {
        System.out.println(Greetings.sayHello());
    }
}

Explanation

• Modules encapsulate packages and provide explicit dependencies between modules.
• The requires keyword specifies module dependencies.
• The exports keyword makes packages accessible to other modules.

Use

• Enhance code organization and maintainability.
• Control and manage dependencies more explicitly.
• Improve security and encapsulation.

Java 10: Local-Variable Type Inference (var)

Java 10 introduced local-variable type inference, allowing the use of the var keyword to declare local variables with inferred types.

Syntax

var variableName = initialValue;

Example

var message = "Hello, Java 10!";

Explanation

• The var keyword infers the type of the variable based on the assigned value.
• Improves code readability and reduces redundancy.

Use

• Enhance code conciseness and reduce boilerplate.
• Improve readability in certain contexts.

Java 11: HTTP Client (Standardized)

Java 11 introduced a standardized HTTP client to provide a more modern and flexible API for sending HTTP requests and receiving responses.

Syntax

HttpClient httpClient = HttpClient.newHttpClient();
HttpRequest request = HttpRequest.newBuilder()
        .uri(URI.create("https://example.com"))
        .build();
HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());

Example

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 httpClient = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://jsonplaceholder.typicode.com/posts/1"))
                .GET()
                .build();

        HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
        System.out.println(response.body());
    }
}

Explanation

• The HttpClient class provides methods for sending HTTP requests.
• HttpRequest and HttpResponse classes represent the request and response, respectively.
• The API supports both synchronous and asynchronous operations.

Use

• Simplify and modernize HTTP communication in Java applications.
• Provides more features compared to the older HttpURLConnection.

Java 12: Switch Expression

Java 12 introduced enhancements to the switch statement, allowing it to be used as an expression, providing a more concise syntax.

Syntax

int result = switch (expression) {
    case value1 -> expression1;
    case value2 -> expression2;
    default -> expression3;
};

Example

public class SwitchExpressionExample {
    public static void main(String[] args) {
        int dayOfWeek = 2;

        String dayType = switch (dayOfWeek) {
            case 1, 2, 3, 4, 5 -> "Weekday";
            case 6, 7 -> "Weekend";
            default -> throw new IllegalStateException("Invalid day: " + dayOfWeek);
        };

        System.out.println(dayType);
    }
}

Explanation

• The switch expression simplifies the syntax and eliminates fall-through cases.
• The arrow -> operator is used to associate a case with an expression.

Use

• Provide a more concise and expressive syntax for switch statements.
• Improve code readability and maintainability.

Java 13: Text Blocks

Java 13 introduced text blocks, allowing multi-line string literals with improved readability and formatting.

Syntax

String textBlock = """
    Line 1
    Line 2
    Line 3
    """;

Example

public class TextBlockExample {
    public static void main(String[] args) {
        String textBlock = """
            Java 13 introduced
            text blocks for
            multi-line strings.
            """;

        System.out.println(textBlock);
    }
}

Explanation

• Text blocks use """ as delimiters.
• Leading and trailing whitespaces are ignored.
• Escaping special characters is not necessary.

Use

• Improve readability of long strings and SQL queries.
• Avoid manual formatting and concatenation.

Important Points

• Stay updated with the latest Java releases to leverage new features and improvements.
• Consider the compatibility of new features with your project's requirements.
• Gradually adopt new features to benefit from enhanced functionality and maintainability.

Summary

Java continues to evolve with each new release, introducing features and enhancements to improve developer productivity, code readability, and maintainability. Embracing new features allows developers to write more expressive, concise, and modern Java code. Stay informed about the latest Java versions and explore how new features can enhance your development experience.