Maven vs Gradle vs Bazel: When to Pick Each Build Tool

All three compile, test, and package JVM code. The differences emerge at the edges — speed at scale, flexibility for custom logic, multi-language support, and reproducibility.

Maven — the convention-over-configuration default

• XML-based pom.xml with a fixed lifecycle: validate, compile, test, package, install, deploy
• Massive plugin ecosystem: Spring Boot plugin, surefire, failsafe, jacoco — most things have an existing plugin
• Strength: any Java engineer can read a Maven project and understand the build; high predictability
• Weakness: when you need custom logic that doesn't fit a plugin, the workaround is painful; no incremental builds, so large projects are slow
• Best for: standard Spring or Jakarta EE microservices, libraries published to Maven Central, projects under ~100k lines of code

Gradle — the flexible DSL with build cache

• Build scripts in Groovy or Kotlin DSL; you can write actual code, define custom tasks, integrate non-JVM languages
• Incremental builds at the task level plus a remote build cache that can be shared across team and CI — huge speedup once you scale past a single developer
• Default for Android (the only well-supported choice); strong for multi-module Java projects
• Trade-off: build scripts can grow into 500-line Groovy beasts; discipline and convention plugins matter
• Best for: Android, multi-module builds, polyglot projects, anywhere build performance is important

Bazel — the monorepo scale-out option

• Originated at Google; hermetic builds where every action's inputs are explicit; sandboxed execution; content-addressable caching; remote execution
• Supports Java, Kotlin, Go, C++, Python, Rust, Swift in one build — the only good option for a true polyglot monorepo
• Massive setup cost: BUILD files everywhere, WORKSPACE for deps, steep learning curve, JVM ecosystem less polished than Maven/Gradle
• Pays off in repos with hundreds of modules and many engineers; over-engineered for a 5-person team
• Examples: Google, Uber, Stripe, Pinterest, Dropbox

The dividing lines

• Build cache value scales with team size — solo dev gets modest gains, team of 50 with remote cache gets order-of-magnitude speedups
• Hermetic builds matter for supply chain security — reproducible builds let you prove what artifacts were built from what source
• Migration cost is brutal — Maven to Gradle is doable, but moving to Bazel is a multi-quarter rearchitecture; pick once

The anti-pattern

• Adopting Bazel for a small project because of "future scale" — the setup cost is real and immediate; the benefit only materializes at scale; migrate when pain justifies cost, not preemptively

The default recommendation

• New Spring service: Maven for simplicity
• Multi-module enterprise codebase, Android, or build performance matters: Gradle
• 100+ engineers in a polyglot monorepo: Bazel, with a dedicated build platform team