I try to use slick and squeryl framework for data persistence with scala. I don't want to use Play framework, but just the persistence framework, but when I import slick (or squeryl) jar file, I encountered the issue below:
slick_2.10.1-2.0.0-M1.jar of <project_name> build path is cross-compiled with an incompatible version of Scala (2.10.1). In case this report is mistaken, this check can be disabled in the compiler preference page.
I used scala jar (2.11.6) under scala plugin on Eclipse, and I can run simple scala application. I can also get access to mysql dbms with jdbc. This problem appears when I import the slick (or squeryl) jar files. Is it because the framework does not support scala 2.11? Is downgrade scala version the solution? If so, can anyone point me a direction on how to downgrade the scala version under Eclipse scala plugin. Thank you very much
If you are using scala 2.11 you need to use this dependency for slick:
<dependency>
<groupId>com.typesafe.slick</groupId>
<artifactId>slick_2.11</artifactId>
<version>3.0.0</version>
</dependency>
The previous answer should resolve your issue with slick. If you'd like to use Squeryl, the dependency should be
<dependency>
<groupId>org.squeryl</groupId>
<artifactId>squeryl_2.11</artifactId>
<version>0.9.6-RC3</version>
</dependency>
Or, if you want to use 0.9.5
<dependency>
<groupId>org.squeryl</groupId>
<artifactId>squeryl_2.11</artifactId>
<version>0.9.5-7</version>
</dependency>
Libraries in Scala are only binary compatible with the minor version of Scala they were compiled against. You'll see that in these examples the correct scala version is appended to the artifact ID with an underscore.
If you have the ability to use SBT instead of Maven, I would recommend it. SBT can choose the proper version for you when you reference a dependency like the following
libraryDependencies += "org.squeryl" % "squeryl_2.11" % "0.9.6-RC3"
Related
I am using akka.http in my Scala code in Intellij. But when I try to build my project I get the following error:
scalac: error while loading Http, class file 'C:\Users\XXXXXX.m2\repository\com\typesafe\akka\akka-http-core_2.13\10.2.9\akka-http-core_2.13-10.2.9.jar(akka/http/scaladsl/Http.class)' is broken
(class java.lang.RuntimeException/error reading Scala signature of Http.class: Scala signature Http has wrong version
expected: 5.0
found: 5.2 in Http.class)
My POM.xml looks like following:
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-actor_3</artifactId>
<version>2.6.19</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.typesafe.akka/akka-http -->
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-http_2.13</artifactId>
<version>10.2.9</version>
</dependency>
My Project structure libraries looks like this:
What Can I do to resolve this error?. Thanks in advance.
I could resolve this issue with latest version of http-akka.
Scala dependencies are built with an specific scala version, and you should match your different dependencies versions, they are also specified in the artifact id after the underscore "_" sign, so you were trying to use an akka-actor_3 scala version 3, with an akka-http_2.13 built for scala version 2.13, so they were uncompatible
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 new to Scala, Spark and Maven and would like to build spark application described here. It uses the Mahout library.
I have Scala IDE install and would like to use Maven to build the dependencies (which are the Mahout library as well as Spark lib). I couldn't find a good tutorial to start. Could someone help me figure it out?
First try compiling simple application with Maven in Scala IDE. The key of Maven project is directory structure and pom.xml. Although I don't use Scala IDE, this document seems helpful.
http://scala-ide.org/docs/tutorials/m2eclipse/
Next step is to add dependency on Spark in pom.xml you can follow this document.
http://blog.cloudera.com/blog/2014/04/how-to-run-a-simple-apache-spark-app-in-cdh-5/
For latest version of Spark and Mahout artifacts you can check them here:
http://mvnrepository.com/artifact/org.apache.spark
http://mvnrepository.com/artifact/org.apache.mahout
Hope this helps.
You need following tools to get started ( based on recent availability) -
Scala IDE for Eclipse – Download latest version of Scala IDE from
here.
Scala Version – 2.11 ( make sure scala compiler is set to
this version as well)
Spark Version 2.2 ( provided in maven
dependency)
winutils.exe
For running in Windows environment , you need hadoop binaries in
windows format. winutils provides that and we need to set
hadoop.home.dir system property to bin path inside which winutils.exe
is present. You can download winutils.exe here and place at path
like this – c:/hadoop/bin/winutils.exe
And, you can define Spark Core Dependency in your Maven POM.XML for your project, to get started with.
<dependency> <!-- Spark dependency -->
<groupId>org.apache.spark</groupId>
<artifactId>spark-core_2.11</artifactId>
<version>2.2.0</version>
<scope>provided</scope>
</dependency>
And in your Java/Scala class define this property, to run on your local environmet on Windows -
System.setProperty("hadoop.home.dir", "c://hadoop//");
More details and full setup details can be found here.
I've discovered that by using json4s native
<dependency>
<groupId>org.json4s</groupId>
<artifactId>json4s-native_2.10</artifactId>
<version>3.2.9</version>
</dependency>
brings scalap and scala-compiler dependencies.
Why does it need it?
Does it generate code on the fly at runtime?
Why doesn't it use macros that do this processing at compile time?
The people of json4s have answered me in this issue the following:
Because we need to read the byte code to find out information about scala primitives. This is more necessary on 2.9 than it is on 2.10
The scala Eclipse plugin requires scala 2.10.0 to run :
To run the 'test' goal on Maven I require the dependency :
<dependency>
<groupId>org.scalatest</groupId>
<artifactId>scalatest_2.9.0-1</artifactId>
<version>2.0.M5</version>
</dependency>
As part of this dependency 'scala-library-2.9.0-1.jar' is also added to build path :
This causes an error to be displayed on problems tab in Eclipse :
More than one scala library found in the build path. At least one has
an incompatible version. Please update the project build path so it
contains only compatible scala libraries.
How can I fix this error ? I need both scala libraries, one is for the scala eclipse plugin and the other for the scalatest maven plugin. I don't want to just delete the error from the problems tab.
The scala Eclipse plugin requires scala 2.10.0 to run :
It has versions for both 2.10 and 2.9, install the one for 2.9.2 (and use ScalaTest for version 2.9.2 as well). Or use a version of ScalaTest for 2.10, but it seems you'll need to build and install it locally, there isn't one for 2.10.0-RC2 listed at http://mvnrepository.com/artifact/org.scalatest.