Unraveling the Maze: The True Aim Behind Project Jigsaw

Java 9's Project Jigsaw stirred up quite the buzz within the Java community, promising a more modular approach to the language. This monumental shift continues to generate both excitement and confusion. In this blog, we aim to demystify the intricacies behind Project Jigsaw, revealing its true aims and implications.

Understanding Modularity

Modularity has been a fundamental aspect of software engineering, and Java has been no exception. However, traditional Java applications often suffered from monolithic structures, making them challenging to maintain and deploy.

Project Jigsaw endeavors to transform this landscape by allowing developers to create a modular Java runtime, breaking down the platform into smaller, interdependent modules. This approach leads to better scalability, maintainability, and reusability, fundamentally altering the way Java applications are developed and deployed.

The Core Objectives of Project Jigsaw

1. Scalability and Performance Optimization

Project Jigsaw aims to enhance scalability by enabling developers to build and deploy custom runtime configurations tailored to their specific application needs. This equips Java applications to run more efficiently, with reduced memory footprints and faster startup times.

2. Encapsulation and Stronger Encapsulation Enforcement

One of the major pain points of traditional Java applications was the lack of true encapsulation between components. With Project Jigsaw, the concept of strong encapsulation is introduced, allowing developers to hide implementation details and restrict access to certain packages and classes, promoting cleaner and more secure code.

3. Dependency Management and Encapsulation

A significant goal of Project Jigsaw is to streamline dependency management by introducing a standardized module system. This facilitates the creation of modular applications with clear dependencies, reducing the risk of dependency conflicts and promoting better code organization.

4. Simplified Development and Maintenance

By embracing modularity, Project Jigsaw aims to simplify the development and maintenance of Java applications, allowing for better code organization and reusability. This, in turn, leads to more manageable and maintainable codebases.

Embracing the Module System

Module Declaration

Let's take a closer look at how modules are declared in Java 9:

module com.example.myapp {
    requires transitive com.example.util;
    exports com.example.myapp.api;
}

In this example, the module keyword declares a module named com.example.myapp. The requires transitive directive specifies that the module depends on com.example.util and also makes its dependencies available to other modules. The exports directive specifies the packages to be exposed to other modules.

Module Path and Resolution

Java 9 introduced the concept of the module path, which allows the JVM to resolve module dependencies. This entails using the --module-path command-line option to specify the directories containing modules, enabling the JVM to locate and load the required modules during application execution.

Modular JARs

With Project Jigsaw, JAR files can now be modular, containing a module descriptor within the META-INF directory. This enables explicit declaration of dependencies and exports, promoting modularization at the JAR level.

Building Modular Application

Let's consider a simple command for compiling a modular Java application:

javac -d mods/com.example.myapp $(find src/com.example.myapp -name "*.java")

In this command, the -d flag specifies the output directory, and the find command gathers all Java files from the source directory. This demonstrates the streamlined approach to compiling a modular Java application.

Navigating the Transition

Compatibility and Migration

As Project Jigsaw redefines the Java landscape, ensuring compatibility and smooth migration for existing applications is paramount. Java 9 provides tools and techniques to ease the transition, including commands to work with non-modular dependencies and libraries.

JLink: Creating Custom Runtime Images

Java 9 introduced the jlink tool, enabling developers to create custom runtime images containing only the modules required for a specific application. This empowers developers to streamline deployments, creating leaner and more efficient runtime environments.

Embracing the Ecosystem

With the modular approach championed by Project Jigsaw, the Java ecosystem has witnessed a shift towards modular design and adoption. Leading frameworks and libraries have embraced modularity, leveraging the benefits of encapsulation, scalability, and dependency management.

Embracing the Future of Java

The introduction of Project Jigsaw represents a seminal shift in the Java ecosystem, ushering in a new era of modularity, scalability, and encapsulation. As developers continue to embrace this transformative approach, it becomes increasingly essential to stay abreast of the evolving landscape and leverage the full potential of Project Jigsaw.

In conclusion, Project Jigsaw strives to revolutionize the way Java applications are developed, deployed, and maintained. By fostering modularity, strong encapsulation, and streamlined dependency management, Java 9 paves the way for a more scalable, efficient, and maintainable ecosystem.

Intrigued by the world of Java modularity? You may find this official Project Jigsaw page insightful. Additionally, the book "Java 9 Modularity" by Sander Mak and Paul Bakker provides a comprehensive exploration of modularity in Java.