Three build tools dominate modern Java: Maven, Gradle, and Bazel. They make different trade-offs between configuration cost, build speed, and flexibility. Most teams pick Maven by default; some pick Gradle for specific reasons; few pick Bazel without a specific scaling need. This page covers what each is good at and how to decide.
Maven
Declarative XML, convention-over-configuration, decades of ecosystem.
Strengths
- Declarative: the POM describes what, not how. Predictable behavior across teams.
- Ecosystem: every Java library publishes Maven artifacts; every IDE supports Maven natively.
- Consistency: the conventions (directory layout, lifecycle phases) are nearly universal.
- Tooling: extensive plugin ecosystem.
Weaknesses
- XML verbosity: large POMs are hard to read.
- Build performance: slower than alternatives at scale.
- Customization friction: non-standard build steps require plugins or workarounds.
- Limited incrementality: Maven re-runs phases more often than Gradle.
When Maven is right
- Standard Java application, no exotic build needs
- Team familiar with Maven
- Heavy use of mainstream Java libraries
- Multi-module project with conventional structure
This describes most Java projects.
Gradle
Configuration-as-code (Groovy or Kotlin DSL), build caching, incremental compilation.
Strengths
- Speed: incremental builds, build caching, daemon process — significantly faster than Maven on large projects
- Flexibility: full programming language for build configuration
- Customization: easy to add custom build steps without plugins
- Multi-language support: Java, Kotlin, Scala, Android, native — all in one build system
- Dependency configuration: more powerful than Maven for complex cases
Weaknesses
- Complexity: full programming language is more powerful and more confusing
- Reproducibility: build configuration can do unexpected things; harder to reason about
- Documentation: improved over time but still less consistent than Maven
- Plugin quality: variable; Maven plugins are generally more polished
- Steep learning curve for the configuration model
When Gradle is right
- Android development (Gradle is the standard)
- Large multi-module project where build performance matters
- Mixed-language project (Kotlin + Java + native)
- Custom build needs that don't fit Maven plugins
Bazel
Hermetic, content-addressed, designed for very large monorepos.
Strengths
- Hermetic builds: every build dependency declared explicitly; results reproducible across machines
- Caching: aggressive remote caching; same output always produces same hash
- Speed at scale: builds with thousands of modules are tractable
- Multi-language: Java, C++, Python, Go, Rust, etc. — all in one build
- Determinism: build outputs are bit-identical given identical inputs
Weaknesses
- Setup cost: high initial complexity
- Ecosystem friction: Bazel doesn't natively understand Maven artifacts; need rules_jvm_external
- Less common: smaller community, fewer learning resources
- Tooling: IDE integration historically weaker than Maven/Gradle
When Bazel is right
- Large monorepo (thousands of modules)
- Multi-language code with shared build infrastructure
- Strong reproducibility requirements
- Engineering culture willing to invest in build infrastructure
This describes Google, Uber, Stripe, etc. For typical applications, Bazel is overkill.
Side-by-side
| Concern | Maven | Gradle | Bazel |
|---|
| Configuration | XML | Groovy/Kotlin | Starlark (Python-like) |
| Speed | Slow | Fast | Very fast at scale |
| Learning curve | Low | Medium | High |
| Multi-language | Mostly Java | Yes | Yes (designed for it) |
| Plugin ecosystem | Extensive, polished | Extensive, variable | Smaller, growing |
| Reproducibility | OK | OK | Excellent |
| IDE support | Excellent | Good | Improving |
| When to use | Default | Performance/customization needs | Large monorepo |
Migration considerations
Maven → Gradle
Gradle has Maven import that converts most POM files. The result is functional but often non-idiomatic Gradle. Migration usually requires manual cleanup; the speedup is real on large projects.
Maven → Bazel
A real undertaking. Maven artifacts have to be exposed via rules_jvm_external or similar; build dependencies have to be declared explicitly per target. For most projects, not worth the effort unless build performance is genuinely a bottleneck.
Some organizations use Maven for libraries (ecosystem compatibility) and Gradle/Bazel for applications (build performance). Possible but adds complexity.
A reasonable default
For new Java projects:
- Default: Maven. Standard tooling, good IDE support, large ecosystem.
- If build speed becomes a real bottleneck: switch to Gradle, accepting the complexity.
- If you're building a monorepo with multiple languages: consider Bazel from the start, accepting the setup cost.
The migration path is one direction usually: Maven → Gradle is feasible; Maven → Bazel is heavy. Plan accordingly.
Common failure patterns
- Picking Bazel for a small project. Setup cost dominates; benefits don't materialize.
- Picking Gradle "for performance" without measuring. Maven is fast enough for many projects; the migration cost may exceed the speedup.
- Custom Maven plugins to do what Gradle does naturally. The complexity creep suggests Gradle may be the better tool.
- Mixing build tools without a plan. Each tool's conventions conflict; cognitive load multiplies.
Further Reading