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Groovy & Gradle: JVM Automation and Build Engineering · Lesson

Resolving Version Conflicts & Dependency Constraints

Diagnose and fix dependency version clashes using the dependency report, resolution strategies, constraints, and forced versions.

Resolving Version Conflicts & Dependency Constraints is a free Groovy & Gradle: JVM Automation and Build Engineering lesson on CoddyKit — lesson 4 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Groovy & Gradle: JVM Automation and Build Engineering learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

The Conflict Problem

Two libraries you depend on may each pull in a different version of the same transitive dependency. Gradle must pick one — and the wrong choice causes runtime errors. Managing this is a core skill.

Default: Newest Wins

By default Gradle resolves a conflict by choosing the highest requested version of a dependency across the graph. Usually safe, but not always.

Seeing the Dependency Tree

The dependencies task prints the full resolved graph, showing which version won and why.

gradle dependencies --configuration runtimeClasspath

Explaining a Single Dependency

The dependencyInsight task explains exactly how one dependency was resolved and who requested each version.

gradle dependencyInsight --dependency guava

Forcing a Version

You can force a specific version, overriding the conflict resolution, with a resolution strategy.

configurations.all {
    resolutionStrategy {
        force 'com.google.guava:guava:32.1.3-jre'
    }
}

Dependency Constraints

The modern approach uses constraints to declare an allowed version without adding the dependency directly — cleaner than force.

dependencies {
    constraints {
        implementation 'com.google.guava:guava:32.1.3-jre'
    }
}

Excluding Transitives

Sometimes a transitive dependency is unwanted entirely. Exclude it from the bringing dependency.

implementation('org.example:lib:1.0') {
    exclude group: 'commons-logging'
}

Rejecting Bad Versions

A resolution strategy can reject known-broken versions so Gradle never selects them.

resolutionStrategy {
    componentSelection {
        all { if (candidate.version == '1.2.0') reject('known bug') }
    }
}

Failing on Conflict

For strict reproducibility, tell Gradle to fail the build whenever a version conflict occurs, forcing you to resolve it explicitly.

resolutionStrategy { failOnVersionConflict() }

Locking Dependencies

Dependency locking writes resolved versions to a lockfile so builds are fully reproducible across machines and time.

gradle dependencies --write-locks

Platforms and BOMs

Import a published BOM with the platform notation to align many related dependencies on one tested version set, avoiding manual version juggling.

dependencies {
    implementation platform('org.springframework.boot:spring-boot-dependencies:3.2.0')
    implementation 'org.springframework.boot:spring-boot-starter-web'
}

Quick Check

Test your conflict resolution knowledge.

Recap

You learned to manage version conflicts:

  • Default resolution picks the highest version
  • Inspect with dependencies and dependencyInsight
  • Override with force or, preferably, constraints
  • exclude removes unwanted transitives; reject blocks bad versions
  • Dependency locking makes builds reproducible

Frequently asked questions

Is the “Resolving Version Conflicts & Dependency Constraints” lesson free?

Yes — the full text of “Resolving Version Conflicts & Dependency Constraints” is free to read here on the web, and the Groovy & Gradle: JVM Automation and Build Engineering course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Groovy & Gradle: JVM Automation and Build Engineering course, upgrade to CoddyKit PRO.

What will I learn in “Resolving Version Conflicts & Dependency Constraints”?

Diagnose and fix dependency version clashes using the dependency report, resolution strategies, constraints, and forced versions. You practise Groovy & Gradle: JVM Automation and Build Engineering with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Groovy & Gradle: JVM Automation and Build Engineering?

No prior experience is required. Groovy & Gradle: JVM Automation and Build Engineering on CoddyKit is structured for beginners through advanced learners; this is — lesson 4 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Resolving Version Conflicts & Dependency Constraints” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Groovy & Gradle: JVM Automation and Build Engineering lesson?

Yes. Every Groovy & Gradle: JVM Automation and Build Engineering lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

  1. Declaring Project Dependencies
  2. Dependency Resolution & Caching
  3. Custom Repositories & BOMs
  4. Resolving Version Conflicts & Dependency Constraints
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