Java 8: What should you know?

Posted by Akshay Sharma on November 6th, 2023

Java is one such word that has captivated the technical world. Java has long been a stalwart in the world of programming languages, powering various applications across different domains. Java has never stopped as it kept on working on upgrading the older versions. 

And undoubtedly, with each new version, Java brings forth enhanced features and functionalities that cater to the evolving needs of developers. 

Its last version, Java 8, released in 2014, has marked a significant milestone in the programming language's history. It has introduced several groundbreaking features that transformed how developers write code.

This article delves into the key Java 8 features and discusses the Java code compilation process using the Java code compiler.

Lambdas: A Paradigm Shift

One of the most prominent Java 8 features is lambdas. 

Lambdas, often called anonymous functions or closures, revolutionized how developers write code by providing a concise and expressive way to represent functionality. 

Before Java 8, achieving functional programming paradigms in Java was lengthy and sometimes cumbersome. Lambdas, however, allow developers to pass around behavior in a much more elegant manner.

Here's a quick example of a lambda expression in Java 8:

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

names.forEach(name -> System.out.println(name));

In this example, the forEach method accepts a lambdas expression as an argument, which defines the behavior for each element in the list.

Stream API: Simplifying Data Manipulation

The Stream API is closely related to lambdas and is another powerful Java 8 feature. Streams provide a streamlined and functional approach to processing data collections, allowing easy filtering, mapping, and reduction operations. This API encourages developers to write more declarative and less imperative code.

Here's an example of using the Stream API to filter and transform data:

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

int sum = numbers.stream()

                .filter(n -> n % 2 == 0)

                .mapToInt(Integer::intValue)

                .sum();

In this code, the stream filters out the odd numbers, maps the remaining even numbers to their integer values, and calculates their sum.

Default Methods: Extending Interfaces

Before Java 8, interfaces could not contain method implementations. That process made adding new methods to existing interfaces challenging without breaking all implementing classes. 

Java 8 introduced the concept of default methods, allowing developers to add new methods with default implementations to interfaces. This feature was introduced to maintain backward compatibility while evolving interfaces.

interface Shape {

    double area();

    default void display() {

        System.out.println("Displaying shape");

    }

}

In this example, the display method has a default implementation. Any class implementing the Shape interface will have this method available without providing an implementation.

Java Code Compilation

Now that we've covered some of the key Java 8 features. Let's briefly touch upon the Java code compilation process. Compilation is essential in the software development lifecycle, as it translates human-readable Java code into machine-executable bytecode.

When you write Java code, you create human-readable text following the Java programming language syntax. The computer's hardware cannot directly execute this code. 

Instead, it needs to be converted into bytecode, a low-level representation of the code that can be understood and executed by the Java Virtual Machine (JVM).

The compilation process involves several steps:

Writing Java Code: You write your Java code in a text editor or an integrated development environment (IDE) such as Eclipse, IntelliJ IDEA, or Visual Studio Code.

Compilation: When you're ready to test or run your code, you save the file with a .java extension. To compile the code, you use the Java compiler (javac), included in the Java Development Kit (JDK). The compiler checks the syntax and semantics of your code, generating bytecode if the code is error-free.

javac YourProgram.java

After successful compilation, you'll have a .class file containing the bytecode.

Bytecode Execution: The Java Virtual Machine (JVM) can now execute the compiled bytecode. The JVM is responsible for interpreting the bytecode and executing the corresponding machine instructions on the underlying hardware.

Just-In-Time Compilation (JIT): Modern JVMs often use a technique called Just-In-Time compilation to improve the performance of Java programs. Instead of interpreting the bytecode every time the program runs, the JVM can dynamically translate it into native machine code just before it's executed. This can result in significantly faster execution.

Execution: With the bytecode translated and optimized by the JVM, your Java program is executed, and you see the results of your code's logic.

Java Versions

Java is a versatile and widely used programming language. It has undergone several versions and updates since its inception in the mid-1990s. These versions have played a crucial role in shaping the language's capabilities and ensuring relevance in a constantly evolving tech landscape.

Java's version history begins with Java 1.0, released by Sun Microsystems in 1996. Over the years, Java has seen numerous updates, including Java 2 (also known as Java 1.2), which introduced significant enhancements like the Swing GUI toolkit, and Java 5, which brought features like generics and the enhanced for loop.

Java 8, released in 2014, was a game-changer with the introduction of lambdas and the Stream API, revolutionizing how developers wrote code for parallelism and functional programming. 

Java 9 introduced the module system, enabling better code organization, while Java 10, 11, and 12 focused on more minor improvements and enhancements.

Java's release cycle changed with Java 13, as Oracle adopted a predictable, time-driven model with a new version every six months. Java 14, 15, and 16 continued to add new features and enhancements, from records and pattern matching to sealed classes.

Java strives to enhance performance, security, and developer productivity with each new version. 

Developers can choose the Java version that best suits their project's needs, benefiting from the language's rich history of innovation and evolution. 

As Java continues to evolve, it remains a powerful tool for building robust, cross-platform applications in a rapidly changing software landscape.

Conclusion

Java 8 features shifted the language paradigm by introducing lambdas, the Stream API, and default interface methods. 

These features empower developers to write more concise, expressive, and functional code, ultimately increasing productivity and maintainability.

Understanding how Java code is compiled is essential for any Java developer. The compilation process, involving converting human-readable code into bytecode and its subsequent execution by the Java Virtual Machine, is a foundational aspect of Java programming.

As you delve into Java 8, take advantage of its powerful features to write cleaner and more efficient code. As you write your code, remember the compilation process that turns your Java code into executable software. This dual understanding will undoubtedly contribute to your success as a Java developer.