Gradle7.x+Android本地Maven依赖嵌套引发NoClassDefFoundError问题

环境 #

• Gradle: 7.1.3
• Kotlin: 1.6.10

依赖场景 #

• 依赖链：localMavenFirstLib（.aar） → localMavenSecondLib（.aar） → localMavenThirdLibTest（Android应用）
• 操作流程：将LocalMavenFirst项目的localMavenFirstLib作为本地Maven依赖引入LocalMavenSecond的localMavenSecondLib，再将localMavenSecondLib作为本地Maven依赖引入LocalMavenThird的应用模块。

问题现象 #

localMavenSecondLib中调用了localMavenFirstLib的Kotlin代码，应用调用localMavenSecondLib代码时崩溃，抛出NoClassDefFoundError，无法找到localMavenFirstLib中的类。

已尝试方案 #

• 切换Gradle的implementation和api依赖配置，无效果；
• 直接在应用模块添加localMavenFirstLib依赖不可行（该库为第三方提供，无法手动引入）。

需求 #

无需手动添加第三方依赖，通过配置实现依赖自动传递，比如将依赖库正确纳入本地Maven仓库的方案。

错误栈信息 #

java.lang.NoClassDefFoundError: Failed resolution of: Lvinit/localMavenFirstLib/LocalMavenFirstLibInfo;
    at vinit.localMavenSecondLib.LocalMavenSecondLibInfo$Companion.getLocalMavenFirstLibInfoIntoLocalMavenSecondLibInfo(LocalMavenSecondLibInfo.kt:24)
    at vinit.localMavenThirdLibTest.LocalMavenThirdLibTestActivity.onCreate(LocalMavenThirdLibTestActivity.kt:17)
    at android.app.Activity.performCreate(Activity.java:8341)
    at android.app.Activity.performCreate(Activity.java:8320)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1417)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3622)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3778)
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:101)
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:138)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2303)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loopOnce(Looper.java:201)
    at android.os.Looper.loop(Looper.java:288)
    at android.app.ActivityThread.main(ActivityThread.java:7884)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:936)
 Caused by: java.lang.ClassNotFoundException: Didn't find class "vinit.localMavenFirstLib.LocalMavenFirstLibInfo" on path: DexPathList[[zip file "/data/app/~~KXIedRpTwdDHSm6h915Y0w==/vinit.localMavenThirdLibTest-RPONyniXEE5kgyC8nthweQ==/base.apk"],nativeLibraryDirectories=[/data/app/~~KXIedRpTwdDHSm6h915Y0w==/vinit.localMavenThirdLibTest-RPONyniXEE5kgyC8nthweQ==/lib/arm64, /system/lib64, /system_ext/lib64]]
    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:259)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
    ... 17 more

解决方案 #

核心问题 #

localMavenSecondLib发布到本地Maven时，未将依赖的localMavenFirstLib信息写入POM文件，导致下游应用无法自动拉取传递依赖。

具体步骤 #

1. 配置localMavenSecondLib的发布脚本：
   在localMavenSecondLib的build.gradle（或build.gradle.kts）中，确保发布任务生成包含依赖信息的POM文件：

   // Groovy版本
   publishing {
       publications {
           maven(MavenPublication) {
               from components.release
               pom.withXml {
                   def dependenciesNode = asNode().appendNode('dependencies')
                   // 处理api依赖（编译期传递）
                   configurations.api.allDependencies.each { dep ->
                       def dependencyNode = dependenciesNode.appendNode('dependency')
                       dependencyNode.appendNode('groupId', dep.group)
                       dependencyNode.appendNode('artifactId', dep.name)
                       dependencyNode.appendNode('version', dep.version)
                       dependencyNode.appendNode('scope', 'compile')
                   }
                   // 处理implementation依赖（运行期传递）
                   configurations.implementation.allDependencies.each { dep ->
                       def dependencyNode = dependenciesNode.appendNode('dependency')
                       dependencyNode.appendNode('groupId', dep.group)
                       dependencyNode.appendNode('artifactId', dep.name)
                       dependencyNode.appendNode('version', dep.version)
                       dependencyNode.appendNode('scope', 'runtime')
                   }
               }
           }
       }
       repositories {
           mavenLocal()
       }
   }
   

   Kotlin DSL版本：

   // Kotlin DSL版本
   publishing {
       publications {
           create<MavenPublication>("maven") {
               from(components["release"])
               pom.withXml {
                   val dependenciesNode = asNode().appendNode("dependencies")
                   configurations.api.get().allDependencies.forEach { dep ->
                       val dependencyNode = dependenciesNode.appendNode("dependency")
                       dependencyNode.appendNode("groupId", dep.group)
                       dependencyNode.appendNode("artifactId", dep.name)
                       dependencyNode.appendNode("version", dep.version)
                       dependencyNode.appendNode("scope", "compile")
                   }
                   configurations.implementation.get().allDependencies.forEach { dep ->
                       val dependencyNode = dependenciesNode.appendNode("dependency")
                       dependencyNode.appendNode("groupId", dep.group)
                       dependencyNode.appendNode("artifactId", dep.name)
                       dependencyNode.appendNode("version", dep.version)
                       dependencyNode.appendNode("scope", "runtime")
                   }
               }
           }
       }
       repositories {
           mavenLocal()
       }
   }
   

2. 使用api引入localMavenFirstLib：
   在localMavenSecondLib的依赖配置中，必须用api引入localMavenFirstLib，确保依赖信息被标记为需要传递：

   // Groovy
   api 'vinit.localMavenFirstLib:localMavenFirstLib:1.0.0'
   

   // Kotlin DSL
   api("vinit.localMavenFirstLib:localMavenFirstLib:1.0.0")
   

3. 重新发布并刷新依赖：

   • 执行localMavenFirstLib的publishToMavenLocal任务；
   • 执行localMavenSecondLib的publishToMavenLocal任务；
   • 刷新localMavenThirdLibTest的Gradle依赖。

验证 #

重新运行应用，localMavenFirstLib的类会被自动纳入应用Dex文件，不再出现NoClassDefFoundError。

内容的提问来源于stack exchange，提问作者Vinit kr28