What version of the scala library jar will support java 1.5 and 1.6
And also how to compile in java?
Scala's jar files are compiled with JVM 1.5, as can be seen by looking into the META-INF/MANIFEST.MF file. Here is 2.8.1: Created-By: 1.5.0_22-b03 (Sun Microsystems Inc.).
The Scala compiler generates output that is compatible with jvm-5 (see scalac -target). Also, it has some magic to enable use with jdk 1.6, in which String has added a method that Scala defines on WrappedString.
Scala is compiled with the scalac compiler and not javac. To run the Scala code you need Java runtime/sdk version 1.5 or later and the scala library jar.
Version 2.7.7 and 2.8.1 are the common versions used today. If you start a new project now you should aim for 2.8.1 or 2.9 (which is going to be available soon-ish). Download site is here
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I am using eclipse with m2eclipse-scala plugin. Currently, I get the following error message:
exampleA_2.10-2.0.1.jar of module build path is cross-compiled with an incompatible version of Scala (2.10.0). In case this report is mistaken, this check can be disabled in the compiler preference page
It looks like the versions of extracted Scala and Scala IDE match. I just wanted to make sure that this is a "false-negative" as described here and can be safely turned off.
As #The Archetypal Paul suggested, it was because I was using wrong Scala library.
If you are using Scala 2.11 (check at About Scala IDE -> installation details), you can downgrade by following instruction here. It's a lot easier than uninstalling and re-installing Scala IDE as other Stackoverflow posts recommend.
I also faced the same issue->
I am trying to use casbah jar in scala to integrate with mongodb.
After analyzing the problem i found that ->
i am trying to use casbah 2.9.1 version and my scala version is 2.11.8
Root-Cause of such error is : your jar is compiled in 2.9.0 version and you are using scala 2.11.8 version
So, to resolve that i use the jar that is compiled into 2.11 scala version-
<groupId>org.mongodb</groupId>
<artifactId>casbah-core_2.11</artifactId>
<version>3.1.1</version>
I was facing similar issue in Eclipse IDE where I had built a Spark scala project in Maven. The scala version was set to 2.11.
Later, I upgraded Scala-Ide plugin in Eclipse after which my project marked below errors,
exampleA_2.10-2.0.1.jar of module build path is cross-compiled with an incompatible version of Scala (2.10.0). In case this report is mistaken, this check can be disabled in the compiler preference page
Right click project folder > scala > set scala version. Here my scala version was displayed as 2.10. I selected 2.11 and removed all the error messages.
I'm trying to build the Apache Crunch source code on my CentOS 7 machine, but am getting the following error in the crunch-spark project when I execute mvn package:
[ERROR] /home/bwatson/programming/git/crunch/crunch-spark/src/it/scala/org/apache/crunch/scrunch/spark/PageRankClassTest.scala:71: error: bad symbolic reference. A signature in PTypeH.class refers to term protobuf
[ERROR] in package com.google which is not available.
[ERROR] It may be completely missing from the current classpath, or the version on
[ERROR] the classpath might be incompatible with the version used when compiling PTypeH.class.
[ERROR] .map(line => { val urls = line.split("\\t"); (urls(0), urls(1)) })
[ERROR] ^
Other SO questions about similar errors (here and here) seem to involve PATH or version issues. I've been messing around but can't seem to resolve them. For completeness:
[bwatson#ben-pc crunch]$ scala -version
Scala code runner version 2.11.5 -- Copyright 2002-2013, LAMP/EPFL
[bwatson#ben-pc crunch]$ java -version
java version "1.8.0_31"
Java(TM) SE Runtime Environment (build 1.8.0_31-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.31-b07, mixed mode)
[bwatson#ben-pc crunch]$ mvn -version
Apache Maven 3.0.5 (Red Hat 3.0.5-16)
Maven home: /usr/share/maven
Java version: 1.8.0_31, vendor: Oracle Corporation
Java home: /usr/java/jdk1.8.0_31/jre
Default locale: en_GB, platform encoding: UTF-8
OS name: "linux", version: "3.10.0-123.20.1.el7.x86_64", arch: "amd64", family: "unix"
Any advice? I'm not really sure where Scala is looking for its dependencies, but I'd have thought that Maven would take care of it.
Unfortunately Different versions of Scala are binary incompatible. Currently by default Apache Spark uses Scala 2.10.4, not Scala 2.11. Apache Scrunch is dependent on Spark. Maven does not know anything about this so it can't help. It is necessary to make some modifications to Scrunch to get it to compile for Scala 2.11 / JDK 1.8. I am working on this at the moment, but I don't have a solution yet. However I get the error message you report if I compile Scala 2.10.4 with JDK 1.8, not Scala 2.11, so I don't think it is doing quite what you intend. The error seems be coming from the Protobuf compiler or jar but I don't know why that is.
When I solve it myself, I will report back!
It turns out the official documentation for Crunch was missing a Maven parameter. The issue was solved by building using:
mvn package -Dcrunch.platform=2
I've got the newest Scala IDE (3.0.2) and I want to compile my stuff with Scala 2.9.3. I've added that version of Scala as a Maven dependency and removed the default 2.10.0 that the IDE bundles with the new project (not my system Scala version, by the way!). The IDE then tells me Scala is not on the build path, even when I add in the jars to the build path. When I try to add a "Scala Library" through that dialogue, it doesn't give me any options and adds 2.10.0. I've gone through the project settings, and would have expected to see a "Scala version" option, but there isn't (only a "Java version" option.)
My question is this:
How do I add a different version of Scala as the Scala library in Scala IDE 3.0.2 ?
Thanks!
I asked a similar question a while back. Short answer is, you can't.
My post:
Scala-IDE 3.0: 2.9.2 -> 2.10.0
I am using the sbtantlr plugin and adapting it to use antlr v3.5. It used to work fine with scala 2.9.2.
Today I upgraded my scala to 2.10.0.
And I compiled the plugin in 2.10.0 and put the plugin 'sbtantlr.jar' in the 'lib' directory of my main scala project.
SBT stopped working with this error message:
Binary incompatibility in plugins detected.
I revert the compiler version to 2.9.2 and it works fine.
Is it because SBT (the official binary release) was built with 2.9? Where can I find the information?
Yes, sbt 0.12.x are built with 2.9x and all plugins need to match the binary Scala version.
To add more information to what Yann said, Scala only guarantees compatibility between minor versions. That is, code compiled with any 2.8.x version is compatible with code compiled with any other 2.8.x version, but no code compiled with 2.8.x is compatible with code compiled by a 2.9.x version.
Now, SBT is a Scala application, and both the plugins and build configuration are libraries to it. SBT 0.12.x was compiled with Scala 2.9.x, so all plugins and project build configuration must also be compiled with Scala 2.9.x.
The project itself can be compiled with any version, as SBT does not need to interact with it.
I am building my first Scala/Play application and after I create and import an eclipse project from the Play shell, I get 17 errors.
akka-actor_2.10.jar is cross compiled with an incompatible version of Scala (2.10)
akka-slf4j_2.10.jar is cross compiled with an incompatible version of Scala (2.10)
anorm_2.10.jar ...
play_2.10.jar ...
play_iterates_2.10.jar ...
The list goes on to include the Scala jars, scalaz jars, etc...
I am using:
Eclipse 4.2.2
Scala ide 3.0.0.nightly-2_09
Scala 2.10
Play 2.1
Has someone experienced the same thing?
Is it possible you are using Scala IDE built for for Scala 2.9.x ?
Make sure you use the one for 2.10.x:
http://download.scala-ide.org/sdk/e38/scala210/dev/site/