Maven转Gradle构建报错：依赖缺失排查与编译配置方案

Issue 1: Gradle referencing JARs not declared in POM or code #

Those "mystery" JARs are almost certainly transitive dependencies—pulled in indirectly by one of your direct dependencies. Here’s how to track them down:

• Generate a full dependency tree: Run this command to visualize every dependency (direct and transitive) for your compile classpath:

  gradle :***-war:dependencies --configuration compileClasspath
  

  Scan the output for the artifact in question; you’ll see exactly which parent dependency is bringing it in.

• Pinpoint the exact source: If the tree is too cluttered, use dependencyInsight to zoom in on the specific artifact:

  gradle :***-war:dependencyInsight --dependency org.mockito:mockito-core --configuration compileClasspath
  

  This will show the full chain of dependencies leading to the unexpected JAR.

• Exclude unwanted transitive dependencies: If the JAR is unnecessary, exclude it from its parent dependency. Example:

  implementation 'com.example:some-dependency:1.0.0' {
      exclude group: 'org.mockito', module: 'mockito-core'
  }
  

Issue 2: Missing mockito-core.jar after Maven-to-Gradle migration #

Even if you don’t reference it directly, mockito-core is a transitive dependency required by another library. Here’s how to fix the resolution error:

1. Identify the parent dependency: Use the dependencyInsight command above to find which library is requesting mockito-core:2.8.9.
2. Verify your repositories: Ensure your Gradle build script includes repositories that host this artifact (like Maven Central):

   repositories {
       mavenCentral()
       // Add any private repos your team uses
   }
   

3. Resolve version conflicts or unavailability:
   • If version 2.8.9 isn’t available in your repos, force a compatible version that exists:

     configurations.all {
         resolutionStrategy.force 'org.mockito:mockito-core:3.12.4'
     }
     

   • Or exclude the problematic transitive dependency and add a valid version explicitly:

     implementation 'org.mockito:mockito-core:3.12.4'
     implementation 'com.example:problematic-dependency:1.0.0' {
         exclude group: 'org.mockito', module: 'mockito-core'
     }
     

Handling POM-only artifacts (no JAR available) #

If a module only has a POM file (common for BOMs, parent POMs, or dependency aggregators), configure Gradle to process it correctly:

• For BOMs (Bill of Materials): Use Gradle’s platform keyword to import the POM and inherit standardized dependency versions:

  implementation platform('com.example:my-bom:1.0.0')
  

• For regular POM-only modules: Declare the dependency with type: 'pom' to ensure Gradle resolves its transitive dependencies:

  implementation 'com.example:pom-only-module:1.0.0', {
      type = 'pom'
      transitive = true // Default behavior, explicit here for clarity
  }
  

• Local POM files: If the POM lives on your filesystem, add a flat directory repository to your build script:

  repositories {
      flatDir {
          dirs '/path/to/pom-directory'
      }
  }
  

内容的提问来源于stack exchange，提问作者Laxmanrao Potadar