Android Studio 上 Kotlin(非安卓)项目的 ClassNotFoundException 错误 [英] ClassNotFoundException error for Kotlin (non-android) project on Android Studio

问题描述

我尝试使用 Android Studio 2.3.3 创建一个普通的 Kotlin 项目(非 Android，只是桌面/命令行项目).

我按照

以下是我的项目文件结构

然后我同步项目，它成功了.但是当我尝试运行该项目时，错误就开始了.我收到以下错误.

 "/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java" -Didea.launcher.port=7534 "-Didea.launcher.bin.path=/Applications/Android Studio.app/Contents/bin" -Dfile.encoding=UTF-8 -classpath "/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/charsets.jar:/Applications/AndroidStudio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/jaccess.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/localedata.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/sunec.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Applications/Android Studio.app/目录/jre/jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/jce.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/jsse.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/management-agent.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/resources.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/rt.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/lib/dt.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/lib/jconsole.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/lib/sa-jdi.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/lib/tools.jar:/Users/haxpor/.gradle/caches/modules-2/files-2.1/org.jetbrains/annotations/13.0/919f0dfe192fb4e063e7dacadee7f8bb9a26072a:/用户/haxpor/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-jre7/1.1.4-2/272a21c30432c943d618008fbbd34762eb0d6c8a/kotlin-stdlib.jars-jre/kotlin-stdlib.1.4/272a21c30432c943d618008/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib/1.1.4-2/fec983b2608a8a91a1b87dba18d247d692cf6b51/kotlin-stdlib-1.jar/xportgradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-jre8/1.1.4-2/168cc3f45c307edda6c867dd0635a7d451257551/kotlin-stdlib.1.48Studio.app/Contents/lib/idea_rt.jar" com.intellij.rt.execution.application.AppMain io.wasin.testjavaapp.Main线程main"中的异常 java.lang.ClassNotFoundException: io.wasin.testjavaapp.Main在 java.net.URLClassLoader.findClass(URLClassLoader.java:381)在 java.lang.ClassLoader.loadClass(ClassLoader.java:424)在 sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)在 java.lang.ClassLoader.loadClass(ClassLoader.java:357)在 java.lang.Class.forName0(Native Method)在 java.lang.Class.forName(Class.java:264)在 com.intellij.rt.execution.application.AppMain.main(AppMain.java:123)进程以退出代码 1 结束

我看到上面提供的类路径参数 /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java 没有与我的项目相关的目录.尽管我已经在配置中进行了设置，但我不知道如何通过 gradle 添加类路径目录.

我该如何解决这个问题?

更新:

以下是我的Main.kt代码.它仅用于测试目的.所以只需打印一些东西.

package io.wasin.testjavaapp对象主{@JvmStatic fun main(arg: Array) {println("你好世界")}}

我还更新了 Kotlin 版本的 build.gradle 以匹配 Android Studio 上的 Kotlin 插件版本.现在是 ext.kotlin_version = '1.1.4-2'.虽然还是没有解决问题.

更新 2

我在 src 目录的同一级别检查了 build 目录.那里没有生成/构建的 .class 或 intermediates 文件，只有 kotlin-build/caches/version.txt 就是这样.没有其他文件.那么问题可能是因为源文件根本没有编译?

更新 3

我尝试创建一个新模块以查看它是否是根本原因.还创建了 assets 文件夹作为工作目录，再次重新排列源文件夹如下.

我们现在有 2 个模块.

1. testJavaApp - 根一
2. desktop - 由 Main.kt 组成，用作桌面可执行文件

testJavaApp 有以下 build.gradle

的代码

group 'io.wasin'版本1.0-快照"//顶级构建文件，您可以在其中添加常见的配置选项所有子项目/模块.构建脚本{ext.kotlin_version = '1.1.4-2'存储库{jcenter()}依赖{类路径 'com.android.tools.build:gradle:2.3.3'类路径org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"//注意:不要将您的应用程序依赖项放在这里；他们属于//在单独的模块 build.gradle 文件中}}所有项目{存储库{jcenter()}}任务清理(类型:删除){删除 rootProject.buildDir}

还有 desktop 模块有以下 build.gradle

的代码

应用插件:'kotlin'sourceSets.main.java.srcDirs = [ "src/" ]project.ext.mainClassName = "io.wasin.testjavaapp.Main"project.ext.assetsDir = new File("../assets");依赖{testCompile 组:'junit'，名称:'junit'，版本:'4.12'编译org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"}存储库{MavenCentral()}任务运行(依赖:类，类型:JavaExec){main = project.mainClassName类路径 = sourceSets.main.runtimeClasspath标准输入 = System.inworkingDir = project.assetsDir忽略退出值 = 真}

不幸的是，它仍然没有工作，并且出现了同样的错误.

更新 4

@aristotll 在评论中提供了信息，他在 Android Studio 中测试并遇到了同样的问题，但在 IntelliJ 中没有.他说这可能是 Android Studio 的错误.所以我想，我会再试几次，然后决定它是否足够可靠，可以报告为错误.感谢您抽出时间进行测试.

解决方案

我也遇到了这个问题，解决了.

在build.gradle中添加runtimeClasspath files("build/classes/kotlin/main")

依赖项{//在此组件和使用者的编译类路径上找到此依赖项.编译 'com.google.guava:guava:23.0'//使用 JUnit 测试框架testCompile 'junit:junit:4.12'编译org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"编译组:'dom4j'，名称:'dom4j'，版本:'1.6.1'运行时类路径文件(build/classes/kotlin/main")}

因为 Android Studio 在 build/classes/kotlin/main 中找不到类.添加 runtimeClasspath 就可以了！

I attempted to create a normal Kotlin project (non-android, just desktop/command line project) with Android Studio 2.3.3.

I followed the steps as laid out here but with different build.gradle content whose content I shared here.

Actually that content of build.gradle I copied from build.gradle file after generating a new project with IntelliJ Community Edition (2017.2).

Then I create a configuration to be able to run it on desktop with proper set up like Main Class, Working directory, and Use classpath of module. You can see in the image below.

and following is the project file structure I have

Then I sync the project, it succeeds. But error kicks in when I try to Run the project. I got the following error.

    "/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java" -Didea.launcher.port=7534 "-Didea.launcher.bin.path=/Applications/Android Studio.app/Contents/bin" -Dfile.encoding=UTF-8 -classpath "/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/charsets.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/jaccess.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/localedata.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/sunec.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/jce.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/jsse.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/management-agent.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/resources.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/rt.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/lib/dt.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/lib/jconsole.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/lib/sa-jdi.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/lib/tools.jar:/Users/haxpor/.gradle/caches/modules-2/files-2.1/org.jetbrains/annotations/13.0/919f0dfe192fb4e063e7dacadee7f8bb9a2672a9/annotations-13.0.jar:/Users/haxpor/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-jre7/1.1.4-2/272a21c30432c943d618008fbbd34762eb0d6c8a/kotlin-stdlib-jre7-1.1.4-2.jar:/Users/haxpor/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib/1.1.4-2/fec983b2608a8a91a1b87dba18d247d692cf6b51/kotlin-stdlib-1.1.4-2.jar:/Users/haxpor/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-jre8/1.1.4-2/168cc3f45c307edda6c867dd0635a7d451257551/kotlin-stdlib-jre8-1.1.4-2.jar:/Applications/Android Studio.app/Contents/lib/idea_rt.jar" com.intellij.rt.execution.application.AppMain io.wasin.testjavaapp.Main
Exception in thread "main" java.lang.ClassNotFoundException: io.wasin.testjavaapp.Main
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:264)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:123)

Process finished with exit code 1

I saw the classpath parameter as supplied in above /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java has no related directory to my project. I don't know how to add classpath directory via gradle despite I set up it in configurations already.

How can I solve this problem?

Update:

The following is my Main.kt code. It's just for testing purpose. So just printing something out.

package io.wasin.testjavaapp

object Main {
    @JvmStatic fun main(arg: Array<String>) {
        println("Hello world")
    }
}

Also I updated build.gradle for Kotlin version to match the version of Kotlin plugin on Android Studio. It's now ext.kotlin_version = '1.1.4-2'. Although still doesn't solve the problem.

Update 2

I checked inside build directory at the same level of src directory. There are no .class or intermediates files generated/built over there, only kotlin-build/caches/version.txt and that's it. No other files. So the problem might be due to the source files are not compiled at all?

Update 3

I tried creating a new module to see if it's the root cause or not. Also created assets folder just to act as Working Directory, rearranged source folder again to be as following.

We now have 2 modules.

1. testJavaApp - root one
2. desktop - consists of Main.kt and used as desktop executable

testJavaApp has the following code for build.gradle

group 'io.wasin'
version '1.0-SNAPSHOT'

// Top-level build file where you can add configuration options common to 
all sub-projects/modules.
buildscript {
    ext.kotlin_version = '1.1.4-2'
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.3'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

also desktop module has following code for build.gradle

apply plugin: 'kotlin'

sourceSets.main.java.srcDirs = [ "src/" ]
project.ext.mainClassName = "io.wasin.testjavaapp.Main"
project.ext.assetsDir = new File("../assets");

dependencies {
    testCompile group: 'junit', name: 'junit', version: '4.12'
    compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
}
repositories {
    mavenCentral()
}

task run(dependsOn: classes, type: JavaExec) {
    main = project.mainClassName
    classpath = sourceSets.main.runtimeClasspath
    standardInput = System.in
    workingDir = project.assetsDir
    ignoreExitValue = true
}

Unfortunately, it still didn't work and it's the same error that shown up.

Update 4

@aristotll provided info in a comment that he tested with Android Studio and faced the same problem, but not with IntelliJ. He said it might be Android Studio bug. So I guess, I would try a few more times then decide whether it's solid enough to report as a bug. Thanks for taking time to testing out.

解决方案

I also met this problem and solved it.

Add runtimeClasspath files("build/classes/kotlin/main") in build.gradle

dependencies {
    // This dependency is found on compile classpath of this component and consumers.
    compile 'com.google.guava:guava:23.0'

    // Use JUnit test framework
    testCompile 'junit:junit:4.12'
    compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
    compile group: 'dom4j', name: 'dom4j', version: '1.6.1'
    runtimeClasspath files("build/classes/kotlin/main")
}

because Android Studio doesn't find classes in build/classes/kotlin/main. Add runtimeClasspath and it works!

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