Utility Gradle task to find where duplicate classes come from (for Gradle 4.1+)

find_in_dependencies.gradle

// H/t to https://github.com/ethankhall/scripts/blob/master/gradle/find-file.gradle for the idea;
// this re-written version actually works in modern Gradle and Android Gradle plugins.

task findInDependencies {
  doLast {
    println()

    def resolvableConfigs = project.getConfigurations()
        .stream()
        .filter { it.isCanBeResolved() }

    resolvableConfigs.each { config ->
      config.resolve()
          .stream()
          .filter {
        //noinspection GroovyPointlessBoolean
        zipTree(it)
            .filter { it.name.startsWith 'Nonnegative' }        // TODO replace `Nonnegative` with what you are looking for
            .each { println "    Match: $it.path" }
            .toList()
            .isEmpty() == false
      }
      .each {
        println "Found in `$config.name: $it.name`\n"
      }
    }
  }
}

This is useful for when your build breaks because of errors such as com.android.dex.DexException: Multiple dex files define L...;.

Common culprits are Findbugs 3.0.1 and its annotations that include the JSR305 annotations, such as javax/annotation/Nonnegative etc. In these cases you need to manually exclude those transitive dependencies from the all those that declare them, and re-declare them explicitly yourself. The dependencies task can be very useful to determine what top-level dependencies transitively include them.

LeftShift has been deprecated and will no longer work with Gradle v5. This can be fixed by using this instead:

task findInDependencies {
  doLast {
    println()

    def resolvableConfigs = project.getConfigurations()
        .stream()
        .filter { it.isCanBeResolved() }

    resolvableConfigs.each { config ->
      config.resolve()
          .stream()
          .filter {
        //noinspection GroovyPointlessBoolean
        zipTree(it)
            .filter { it.name.startsWith 'Nonnegative' }        // TODO replace `Nonnegative` with what you are looking for
            .each { println "    Match: $it.path" }
            .toList()
            .isEmpty() == false
      }
      .each {
        println "Found in `$config.name: $it.name`\n"
      }
    }
  }
}

Thanks, I have incorporated it in the main gist