ClassNotFoundException:scala.PreDef$ 问题
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ClassNotFoundException:scala.PreDef$ issue
提问by Andy
Hi guys I am trying to package a simple executable Jar written in Scala, through Eclipse's Export function.
大家好，我正在尝试通过 Eclipse 的导出功能打包一个用 Scala 编写的简单可执行 Jar。
When attempting to execute the Jar from cmd java -jar test2.jar
尝试从 cmd 执行 Jar 时 java -jar test2.jar
I get the following.... Any ideas? Thank you.
我得到以下....有什么想法吗？谢谢你。
Caused by: java.lang.NoClassDefFoundError: scala/Predef$
at Parser.Test(Parser.scala:5)
at Main.main(Main.java:12)
... 5 more
Caused by: java.lang.ClassNotFoundException: scala.Predef$
at java.net.URLClassLoader.run(Unknown Source)
at java.net.URLClassLoader.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 7 more
回答by Régis Jean-Gilles
You just need to add the scala library jar to the classpath.
您只需要将 Scala 库 jar 添加到类路径。
You can do it like this (assuming that the "scala-library.jar" jar is in the current directory) :
您可以这样做（假设“scala-library.jar”jar 在当前目录中）：
java -cp scala-library.jar -jar test2.jar
The documentation for tha javacomamnd can be found here: http://docs.oracle.com/javase/6/docs/technotes/tools/windows/java.html
java可以在此处找到该命令的文档：http: //docs.oracle.com/javase/6/docs/technotes/tools/windows/java.html
回答by Shaaban Ebrahim
for me i was using jdk 11 and scala library container 2.12.3 and when i changed to jdk 8 it works fine it is because of jdk11 scala version support JDK Compatibility
对我来说，我使用的是 jdk 11 和 scala 库容器 2.12.3，当我更改为 jdk 8 时它工作正常，这是因为 jdk11 scala 版本支持 JDK 兼容性
right click on the project , Build path ,configure Build path , edit your jdk to less than 11
右键项目，构建路径，配置构建路径，将你的jdk编辑为小于11
回答by rarry
回答by Leon Rom
I did removed"Scala Library container" from project. Next - addneeded scala's library (scala-library.jar) to Java BuildPath(in Properties for) as "Add External JARs..." in mylibrary (not as reference to scala lib). And innclude them all to "Order and Export" Finally- do Exportfor project with option "Package required libraries into generate JAR" and this works fine :)
我确实从项目中删除了“ Scala 库容器”。下一步-添加需要Scala的库（斯卡拉-library.jar）到Java的构建路径（在为属性）为“添加外部JAR ...”在我的库（而不是作为参考斯卡拉LIB）。并将它们全部包含到“订购和导出” 最后-使用选项“将所需的库打包到生成 JAR 中”为项目进行导出，这很好用:)
