Build automation tools, or build tools, are applications used for build automation. Build automation is an important aspect of software development. It refers to the process of automating the tasks necessary to turn source code into executable programs. Your choice of build tool would depend on the languages and frameworks you’re using.
Today, we’ll focus on Java build tools. Java is one of the most commonly used languages in software development. There are many Java build tools available. We’ll compare two of the most popular build tools for Java development: Maven and Gradle.
We’ll cover:
- What is build automation?
- What do build tools do?
- What is Maven?
- What is Gradle?
- Maven vs Gradle: Similarities
- Maven vs Gradle: Differences
- Maven vs Gradle: Which Java build tool is right for you?
- Wrapping up and next steps
What is build automation?
Build automation is the process of automating the tasks necessary to create, execute, and test programs. After you create the source code for a program, build automation comes in to process and prepare the source code for deployment to production.
Build automation is a best practice and prerequisite for any continuous integration process in DevOps. Most modern development teams have an established build automation process. These task automations help save valuable time and resources for developers and development teams, who once carried out these tasks manually.
Build automation tasks were historically accomplished using makefiles. Today, they are done using build automation tools or build automation servers. The term build automation can be used interchangeably with build systems.
What do build tools do?
Build tools facilitate a wide variety of build automation tasks, including:
- Compiling: Compiling source code into machine code
- Dependency management: Identifying and patching necessary third party integrations
- Automated tests: Executing tests and reporting failure
- Packaging app for deployment: Prepares source code for deployment to servers
What is Maven?
Maven, or Apache Maven, was released in 2004 as an improvement to Apache Ant. It is an XML-based build tool and project manager. Maven is an Apache open-source project. Its default repository is the Maven Central Repository. The Central Repository consists of open-source components from contributors ranging from individual developers to large organizations. There is a vast array of Maven plugins to customize and expand the build tool’s functionality.
Maven projects are primarily defined by Project Object Model (POM) files written in XML. These POM.xml files contain the project’s dependencies, plugins, properties, and configuration data. Maven uses a declarative approach and has a predefined life cycle.
What is Gradle?
Gradle was first released in 2008. Building on Maven’s concepts, it was introduced as Maven’s successor. Rather than using Maven’s XML-based project configuration, it introduced a domain-specific language (DSL) based on the Groovy and Kotlin programming languages. Gradle supports Maven and Ivy repositories for declaring project configurations. It was designed with multi-project builds in mind.
Maven vs Gradle: Similarities
Both Maven and Gradle are free and open-source software distributed under the Apache License 2.0. They are both highly customizable and supported by various Java IDEs, including Eclipse.
More similarities between Maven and Gradle include:
- GAV format used to identify artifacts
- Plugins add functionality, including adding tasks and dependency configurations to projects
- Same directory structure (Gradle adopted Maven’s)
- Both resolve dependencies from configurable repositories
Maven vs Gradle: Differences
Some of the key differences between Maven and Gradle are:
- Build script language: Gradle’s build script is inherently more versatile and powerful than Maven’s. This is because Gradle is based on a programming language (Groovy), while Maven’s is based on a markup language (XML). The caveat here is that Gradle’s build script is vulnerable to bugs since it's based on a programming language.
- Performance: Gradle implements strategies such as build cache and incremental compilations to enable fast performance. Gradle claims that it runs up to seven times faster than Maven for incremental changes, and three times faster when task outputs are cached. Take this with a grain of salt though. There are developers out there who find Maven the faster of the two.
- Flexibility and ease of customization: Gradle’s Groovy-based build script offers more immediate flexibility than Maven’s XML. For instance, you can write plugin customizations directly into Gradle’s build script. Gradle is also more powerful when you want to customize build artifacts and project structure. While Maven is also highly customizable, its XML-based configuration requires a few extra steps to customize your build.
- Plugins: Maven has been around longer than Gradle. For that reason, there are more Maven plugins available, and more major vendors support Maven plugins than Gradle plugins.
- Dependency management: The two build tools use different approaches to resolve dependency conflicts. Maven follows a declaration order, while Gradle references a dependency tree.
Maven vs Gradle: Which Java build tool is right for you?
Choosing a Java build tool is largely up to your individual preferences and project requirements.
Here are some things to consider if you’re deciding between Gradle and Maven:
- Typical project size: If you work on large projects, Gradle might perform better and faster than Maven. If you mainly handle smaller projects, the difference in Maven’s performance can be negligible or irrelevant for your decision.
- Need for customization: Gradle’s Groovy-based build script easily permits customization if your project needs lots of bells and whistles. Maven might sufficiently meet your needs if you don’t mind the extra steps involved in adding functionalities to its XML-based script.
- Learning curve: Gradle is known to have a steep learning curve, even for seasoned build engineers. This learning curve is a worthy investment of time and energy if you know Gradle will be the right long-term fit for you. However, it may be an unnecessary uphill battle to learn Gradle if Maven can adequately meet your needs.
- Community support: Maven’s community was already established before Gradle entered the stage. Maven may better meet your needs if community support and documentation is important to you.
Wrapping up and next steps
Choosing a build tool will depend on your individual needs. Whether you’re in DevOps or software development, Java build tools like Maven and Gradle are invaluable utilities. Since both are free, you could consider trying both to make an informed decision.
To help empower Java developers, Educative has created The All-in-One Guide to Java Programming course. This course covers Java fundamentals and uses an interactive approach to familiarize you with Java development tools, including Maven and Gradle.
Happy learning!
Top comments (3)
Gradle claims about build performance have nothing to do with reality - Maven builds are usually faster, especially for clean builds.
Maven configuration is much cleaner and simpler to understand and maintain, even for projects one is less familiar with. Gradle configuration is always different and every time one needs to understand it from scratch.
Maven is much better suited for larger projects, with deep nested structure. Gradle for long time required external plugin for centralized dependency management, for example. Maven projects naturally organized into nested modular structure, where each module contains necessary information to build it and its submodules. Often submodules can be built independently, without need to start build at the top level. Gradle uses centralized structure, where top level project knows all other subprojects, no matter how deeply they are nested.
This difference does not feel important until one needs to merge several independent projects into monorepo. Maven approach to configuration organization makes such a transition relatively simple. For Gradle this is quite complicated and sometimes tricky task.
Maven is much better backward compatible than Gradle. Old projects could be easily built with recent Maven version. This is not the case for Gradle. Upgrading Gradle build configuration for new version of Gradle is complicated and painful task given misleading error messages and useless documentation. In general this applies to virtually any issue with Gradle build - if you encounter something, be prepared for long googling, experimenting and guessing.
Still some issues are not fixed for years because nobody (including authors) can understand how they are happening. And only with Gradle I've encountered some bizarre behaviors even with well-known and proven tools. For example in one project I've observed how JUnit tries to pick up inner classes(!) of utility class(!) as a test. Excluding doesn't work (and why top class which has no 'Test' in name is even considered?), so inner class is marked as @Ignored. Which, in turn, triggers JUnit exception during build. Fortunately, this exception is ignored by Gradle so build passes.
Overall Gradle is good fit for Spring projects - both tools make development a constant fight with their "magic" which takes long hours and days. In turn they save you few seconds or even minutes by eliminating some boilerplate. Fantastic deal, isn't it?
Thanks for sharing your input Sergiy! It's interesting to hear about everyone's experience with the tools. I definitely heard many Gradle users experience "long googling" too -- I might have to add that to this article ;)
I am trying learn more about gradle since I ve been using maven for a long time, I heard some good benefits in the flexibility of the syntax