Introduction to Gradle

Gradle is an open-source construction tool that is capable of controlling the development tasks with compilation and packaging, including testing, deployment and publishing. 

• It is an automation tool that is based on Apache Ant and Apache Maven.
• This tool is capable of developing applications with industry standards and supports a variety of languages, including Groovy, C++, Java, Scala and C.

Working of Gradle

The Gradle project, when constructed it consists of one or more projects. These projects consist of tasks. Let us understand the basics of both terms.

1. Gradle Projects: The projects created by Gradle are a web application or a JAR file. These projects are a combination of one or more tasks. These projects are capable of being deployed on various development life cycles. A Gradle project can be described as building a wall with bricks N in number, which can be termed as tasks. 

2. Gradle Tasks: The tasks are the functions that are responsible for a specific role. These tasks are responsible for creating classes, Javadoc, or publishing archives into the repository, which makes up the whole development of the Gradle project. These tasks help Gradle decide what input is to be processed for a specific output. Again, tasks can be categorized in two different ways: 

• Default Task: These are the predefined tasks that are provided to users by Gradle. These are provided to users prior which executing when the users do not declare any task on their own. For example, init and wrap the default tasks provided to users into a Gradle project
• Custom Task: Custom tasks are the tasks that are developed by the developer to perform a user-defined task. These are developed to run a specific role in a project. Let's take a look at how to develop a Custom Task below.

Example: Printing Welcome to GeeksforGeeks! with a task in Gradle.  

build.gradle : task hello
{
    doLast
    {
        println 'Welcome to GeeksforGeeks!'
    }
}

Output: 

> gradle -q hello
Welcome to GeeksforGeeks!

Features of Gradle

• IDE Support: Compatible with popular IDEs, making development seamless across environments.
• Java Compatibility: Requires the JVM to run and supports Java APIs, making it familiar for Java developers.
• Build System Integration: Supports features from Ant and Maven, including importing Ant projects and using Maven repositories.
• Incremental Builds: Only recompiles code that changed since the last build, reducing build time.
• Open Source: Free and open-source under the Apache License with strong community support.
• Multi-Project Builds: Efficiently handles complex project structures with multiple sub-projects.
• Dependency Management: Automatically resolves and downloads project dependencies.
• Scripting with Groovy/Kotlin DSL: Offers flexible scripting for build configurations.
• Plugins: Offers a wide range of plugins to support various languages and technologies like Java, Android, C++, etc.
• Extensibility: Highly customizable through APIs and plugin development.
• Build Caching: Speeds up builds by reusing outputs from previous builds.
• Test Automation: Supports testing frameworks like JUnit, TestNG and Spock, with code coverage tools.
• Continuous Integration: Easily integrates with CI tools like Jenkins and TeamCity.
• Multi-Language Support: Supports Java, Groovy, Kotlin, Scala and more.

History of Gradle

Gradle is the most stable tool when compared to Ant and Maven. This tool was released in late 2007 initially as an alternative to predecessors, which not only replaced them but also covered the drawbacks of. Its stable version was released in the year 2019 and is now currently with the latest version 6.6. 

Pros of Using Gradle

• Declarative and Scalable: Uses a clear DSL for configuration and scales well with project size.
• Flexible Structure: Adapts to any project layout and supports custom plugins.
• Deep API Access: Allows detailed control over build execution and behavior.
• Improved Performance: Optimized for faster builds, even in large projects.
• Strong Community: Offers rich documentation, tutorials and plugin resources.

Cons of Using Gradle

• Learning Curve: Requires knowledge of Groovy/Java and an understanding of Gradle’s architecture.
• Complex Configuration: Setup and plugin integration can be tricky for beginners.
• Debugging Difficulty: Troubleshooting can be hard in large builds with many dependencies.
• Resource Intensive: Can consume significant system resources during builds.
• Migration Challenges: Transitioning from other build tools may require significant effort and expertise.