scala 当我尝试运行此代码时，为什么会出现 java.lang.NoClassDefFoundError？
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Why do I get java.lang.NoClassDefFoundError when I trying to run this code?
提问by mcandre
I want to map over the characters in a string, but I'm getting runtime errors.
我想映射字符串中的字符，但出现运行时错误。
Example:
例子：
object Hello {
def hello(c: Char) {
print(c)
}
def main(args: Array[String]) {
"Hello World!".map(hello)
}
}
Trace:
痕迹：
scalac Hello.scala
java Hello
Exception in thread "main" java.lang.NoClassDefFoundError: scala/LowPriorityImplicits
at Hello.main(Hello.scala)
Caused by: java.lang.ClassNotFoundException: scala.LowPriorityImplicits
at java.net.URLClassLoader.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
... 1 more
make: *** [test] Error 1
回答by fhuertas
I think that your problem is that scala library is not in your runtime classpath. you must manually add manually.
我认为您的问题是 Scala 库不在您的运行时类路径中。您必须手动手动添加。
If you are using tools like maven or sbt, maybe the dependency is marked as provided instead compiled.
如果您使用的是 maven 或 sbt 之类的工具，可能依赖项被标记为提供而不是编译。
If you are not using these tools, add "scala-library.jar" to your library directory
如果您不使用这些工具，请将“scala-library.jar”添加到您的库目录中
回答by Yuchen Zhong
Also seeing this problem because I don't have the right version of Scala. For those who are using IntelliJ, you can add/change the scala SDK under File> Project Structures> Global Libraries:
也看到这个问题，因为我没有正确版本的 Scala。对于使用 IntelliJ 的用户，您可以在File> Project Structures> Global Libraries下添加/更改 scala SDK ：
If you are compiling and running your project in command line, make sure you have the right version of Scala installed too. e.g.:
如果您在命令行中编译和运行您的项目，请确保您也安装了正确版本的 Scala。例如：
Check the Scala version installed:
检查安装的 Scala 版本：
$ scala -version
Scala code runner version 2.11.8 -- Copyright 2002-2016, LAMP/EPFL
Check the build.sbtto have the right version of Scala:
检查build.sbt以获得正确版本的 Scala：
scalaVersion := "2.11.8"
