Gradle vs. Maven: Which Build System Is Right for Your Java Project?

23.02.2023 — java — 6 min read

When it comes to building and managing Java projects, there are two popular build systems: Gradle and Maven. Both are powerful tools with their own unique features and benefits, but choosing the right one can be a daunting task.

What Is a Java Build System and Why Is It Needed?

A build system is a software tool that automates the process of building and managing software projects. In the context of Java, a build system is used to compile source code, package compiled code into JAR files, manage dependencies, and perform other tasks required to build and distribute a Java application.

Build systems are essential for streamlining the development process, reducing errors, and improving overall project management.

Gradle

Gradle is a build automation tool that uses a Groovy-based configuration file, build.gradle, to define project settings and dependencies.

One of the key advantages of Gradle is its flexibility and extensibility. It allows developers to customize and extend the build process using a powerful and expressive domain-specific language (DSL) based on Groovy.

Gradle's incremental build feature allows developers to rebuild only the parts of the project that have changed, significantly reducing build times for large projects.

However, Gradle can have a steeper learning curve than Maven, and its flexibility can lead to complexity and maintenance challenges for larger projects.

Pros

Flexible and extensible using Groovy-based DSL
Incremental build feature reduces build times
Powerful and expressive domain-specific language

Cons

Steeper learning curve than Maven
Flexibility can lead to complexity and maintenance challenges

Gradle Groovy-Based Configuration File

The Gradle configuration file, build.gradle, is written in Groovy and defines the project and its dependencies. Here is a breakdown of some of the key elements in the file:

plugins: This section specifies which plugins are applied to the project.
repositories: This section lists the repositories where Gradle will look for dependencies.
dependencies: This section lists all the dependencies required for the project to compile and run.
task: This section defines tasks that can be run as part of the build process.

Here is an example of a build.gradle file:

plugins {
    id 'java'
}

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework:spring-core:5.3.13'
    implementation 'com.google.guava:guava:30.1.1-jre'
}

task compileJava(type: JavaCompile) {
    options.encoding = 'UTF-8'
}

Let's break it down section by section:

plugins: This is declaring the 'java' plugin. This plugin provides the basic functionality to build and run a Java project.
repositories: This section declares that the project will fetch depedencies from the Maven Central repository, which is a widely-used repository of Java libraries.
dependencies: This section lists the Spring Framework's spring-core library and Google's guava library as dependencies. These libraries provide additional functionality to the Java project.
task: This section declares a custom Gradle task named compileJava, which is a type of JavaCompile. This task is executed when the project is compiled. The options.encoding line sets the encoding to UTF-8.

In summary, this Gradle file declares the Java plugin and its dependencies, including Spring Framework and Google's Guava library, and defines a custom compile task with UTF-8 encoding.

Maven

Maven is a widely used build automation tool primarily used for Java projects. It uses an XML configuration file, pom.xml, to define project settings and dependencies.

Maven has a large and active community, with a vast repository of plugins that enable developers to customize and extend its functionality. Maven also has robust dependency management features, which can automatically download and manage project dependencies from a central repository.

One of the key benefits of using Maven is its convention-over-configuration approach, which simplifies project setup and configuration by providing default settings that work for most projects.

However, Maven's XML configuration can be verbose and difficult to read, especially for complex projects. Additionally, Maven's rigid structure can make it challenging to customize and extend beyond its default behavior.

Pros

Convention-over-configuration approach simplifies project setup and configuration
Robust dependency management system
Large and active community with extensive plugin repository

Cons

Verbose and difficult-to-read XML configuration
Limited flexibility and extensibility beyond default behavior

Maven XML Configuration File

The Maven XML configuration file, pom.xml, is the main configuration file for Maven projects. It contains project information, dependencies, build settings, and more. Here is a breakdown of some of the key elements in the file:

project: This is the root element of the configuration file and contains all the project information.
modelVersion: This specifies the version of the Maven model used to build the project.
groupId, artifactId, and version: These three elements identify the project and are used in generating the artifact's coordinates.
dependencies: This section lists all the dependencies required for the project to compile and run.
build: This section specifies the build settings for the project, including plugins, directories, and more.

Here is an example of a pom.xml file:

<project>
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>my-project</artifactId>
    <version>1.0.0</version>
    
    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>5.3.13.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>30.1.1-jre</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
            </plugin>
        </plugins>
    </build>
</project>

Let's break this down by sections:

modelVersion: This specifies the version of the Project Object Model (POM) that the file follows as 4.0.0.
groupId: This specifies the group ID of the project as 'com.example'.
artifactId: This specifies the name of the project's artifact (i.e., the name of the resulting JAR file) as 'my-project'.
version: This specifies the version of the project as 1.0.0.
dependencies: This lists the project's dependencies as spring-core and guava.
build: This section specifies maven-compiler-plugin as a plugin that is responsible for compiling the project's source code into bytecode.

In summary, this Maven configuration file specifies the group ID, artifact ID, and version number of the project, and lists the dependencies of the project as Spring Framework and Guava libraries. It also specifies the Maven Compiler Plugin version to be used in building the project.

Final Thoughts

Both files specify dependencies, build settings, and project metadata, but the syntax and structure are quite different. While Gradle uses Groovy for its build files, Maven uses XML. However, both build systems provide similar functionality and achieve the same end goal.

In general, Gradle is often preferred for its flexibility and its support for incremental builds, which can save time and resources when developing larger projects. Maven, on the other hand, has a larger community and ecosystem, with many plugins and integrations available out of the box.

Ultimately, the choice between Gradle and Maven will depend on the specific needs of your project and team. It's worth exploring both options and experimenting with each to see which works best for your particular use case.