[英]How can I use Scala with JDK 1.7? (Unsupported major.minor 52.0 Error)
this "unsupported major.minor 52.0 version" error is driving me nuts. 这个“不受支持的major.minor 52.0版本”错误使我发疯。
How can I get scala to use jdk 1.7. 我如何获得Scala以使用jdk 1.7。 My SBT project needs to be 1.7 and I cannot run sbt or scala unless I set my java_home to 1.8.
我的SBT项目需要为1.7,除非将java_home设置为1.8,否则我将无法运行sbt或scala。
My google foo is not strong since there are so many results for this vague-keyword problem. 我的谷歌foo不强,因为这个模糊关键字问题有很多结果。
Do I need to install different version of scala? 我需要安装不同版本的Scala吗? sbt?
sbt?
Thanks, 谢谢,
Edit More details: 编辑更多详细信息:
$ java -version
java version "1.7.0_80"
Java(TM) SE Runtime Environment (build 1.7.0_80-b15)
Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode)
$ echo $JAVA_HOME
/Library/Java/JavaVirtualMachines/jdk1.7.0_80.jdk/Contents/Home
$ sbt -sbt-version 0.13.16 ~jetty:start
[info] Loading project definition from /Users/dan/Projects/temp/ssltester/project
[info] Set current project to ssltester (in build file:/Users/dan/Projects/temp/ssltester/)
[info] starting server ...
[success] Total time: 0 s, completed Nov 7, 2017 4:35:49 PM
1. Waiting for source changes... (press enter to interrupt)
Exception in thread "main" java.lang.UnsupportedClassVersionError: org/eclipse/jetty/runner/Runner : Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)
[info] waiting for server to shut down...
build.sbt build.sbt
name := "ssltester"
version := "1.0"
scalaVersion := "2.11.11"
resolvers += "Sonatype OSS Snapshots" at "https://oss.sonatype.org/content/repositories/snapshots"
libraryDependencies += "org.scala-lang.modules" %% "scala-xml" % "1.0.2"
libraryDependencies += "javax.servlet" % "javax.servlet-api" % "3.0.1" % "provided"
libraryDependencies += "org.codehaus.groovy.modules.http-builder" % "http-builder" % "0.5.2"
enablePlugins(JettyPlugin)
./project/build.sbt ./project/build.sbt
addSbtPlugin("com.earldouglas" % "xsbt-web-plugin" % "3.0.1")
Scala 2.12 requires a Java 8 JVM and library . Scala 2.12需要Java 8 JVM和库 。 You will either have to use a current version of Java or an outdated version of Scala.
您将不得不使用Java的当前版本或Scala的过时版本。
Traits now compile to interface
s with default
methods, and Scala lambdas use the same encoding as Java 8 lambdas do. 特性现在可以使用
default
方法编译为interface
,并且Scala lambda使用与Java 8 lambda相同的编码。 Java 8 lambdas are mostly a library feature and could be backported , but method implementations in interfaces are a backwards-incompatible change to the bytecode language. Java 8 lambda大多是库功能,可以向后移植 ,但是接口中的方法实现是字节码语言的向后不兼容更改。
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