Dependency conflict when resolving Gradle build

[thesunwillriseup]

I’m running into a dependency conflict in my Gradle project. When I try to build, Gradle fails with a version resolution error.

Steps to Reproduce:

Clone the repo

Run ./gradlew build

Observe dependency resolution error

Expected Behavior:
Gradle should resolve dependencies without conflict and complete the build successfully.

Actual Behavior:
Build fails with an error similar to:

Execution failed for task ':app:dependencies'.
Could not resolve all files for configuration ':app:runtimeClasspath'.
Conflict with dependency 'com.google.guava:guava' in project ':app'. 
Resolved versions for app (30.1-jre) and test (31.0.1-jre) differ.

Environment:

Gradle version: 8.5

Java version: 17

OS: macOS 14.3

Additional Context:
This started happening after adding com.google.firebase:firebase-core:21.1.0.

[CodeVoyager15]

This conflict happens because different parts of the project (main vs test dependencies) are pulling in different versions of Guava. To fix it, you can force Gradle to use a single consistent version.

In your build.gradle (project-level), add a resolution strategy:

configurations.all {
    resolutionStrategy {
        force 'com.google.guava:guava:31.0.1-jre'
    }
}

Alternatively, you can declare a dependency constraint (Gradle’s recommended way):

dependencies {
    implementation 'com.google.guava:guava:31.0.1-jre'

    constraints {
        implementation('com.google.guava:guava:31.0.1-jre') {
            because 'Align all modules on the same Guava version to avoid conflicts'
        }
    }
}

Then run:

./gradlew clean build

This ensures all configurations (main, test, transitive) resolve to the same Guava version.

[CodeVoyager15]

Try this in the root build.gradle:

subprojects {
  configurations.all {
    resolutionStrategy {
      force("com.google.guava:guava:31.0.1-jre")
    }
  }
}

Or use a dependency constraint in the root:

dependencies {
  constraints {
    implementation("com.google.guava:guava:31.0.1-jre") {
      because("align guava across modules")
    }
  }
}

After that, run:

./gradlew --refresh-dependencies clean build

If you’re still seeing conflicts, please run:

./gradlew :app:dependencyInsight --configuration runtimeClasspath --dependency guava