When I run a worksheet in IntelliJ Idea 12 (sbt plugin, Scala project), I've got an error of:
> Failed to initialize compiler: class scala.reflect.BeanInfo not found.
** Note that as of 2.8 scala does not assume use of the java classpath.
** For the old behavior pass -usejavacp to scala, or if using a Settings
** object programatically, settings.usejavacp.value = true.
Everything what has to be set up, is setup: sbt, dependencies, etc, that is if run this project using sbt command line (compile, run), it will run successfully.
Of course, I ran sbt gen-idea.
What do I do?
My solution:
I created a new Scala project with IntelliJ IDEA and set the Scala home to the manually downloaded and unpacked Scala folder for Scala 2.10.2.
Now you can set the Scala compiler in the real project:
Switch to the real project, open the project structure settings and then Modules | your module name | Scala | compiler library. Switch to your new version.
Set the language level to 2.10.
Related
I am trying to compile the scala/Play framework example application on my local machine, but I am getting compilation errors when trying to compile using the SBT console in IntelliJ:
error: scala.reflect.internal.MissingRequirementError: object java.lang.Object in compiler mirror not found.
I also got this message in the event log related to different SBT versions:
14:48 Started sbt shell with sbt version 0.13.18 instead of 0.13.11 configured by project.
Update sbt version
Disable version override
Any suggestions on how to fix this?
For the first error
error: scala.reflect.internal.MissingRequirementError: object java.lang.Object in compiler mirror not found.
You might want to try and ensure that you are using a compatible java version. Like #cbley suggested, try making you are using version 8 of the JDK.
For the second error
14:48 Started sbt shell with sbt version 0.13.18 instead of 0.13.11 configured by project.
Update sbt version
Disable version override
Its just suggesting you update the version of sbt (which is most likely declared in your build.properties file in a folder called project. You can just search for it by double tapping shift in IntelliJ. But you are safe to ignore it if you cloned some example repository as well.
check
I am porting a small legacy library from scala 2.12 to scala 2.13. sbt version is 1.3.3. The project is flat and relatively simple. scalaVersion declared in the project is 2.13.1.
I am executing clean and compile tasks, and then publish to both local ivy and to the artifactory.
The process seemingly goes fine and creates the artifact with the _2.13 suffix. When this binary gets executed against scala 2.13 runtime, it fails with MethodNotFound exception. Further introspection shows that the artifact was compiled for 2.12 but not for 2.13.
Does anybody have an idea why a different compiler version was used by sbt, and how to fix this problem?
Just had similar issue, sbt was compiling my project to the wrong Scala version, found this question without answers in google.
So, my problem was actually very simple. Turns out you need to start sbt in a project root directory (where build.sbt is located). I was running it from a directory where all my .scala files were located, so it haven't parsed build.sbt and compiled project using default Scala version (2.12 in my case).
I have some main object:
import org.apache.spark.SparkConf
import org.apache.spark.SparkContext
import org.apache.spark.SparkContext._
object Main {
def main(args: Array[String]) {
val sc = new SparkContext(
new SparkConf().setMaster("local").setAppName("FakeProjectName")
)
}
}
...then I add spark-assembly-1.3.0-hadoop2.4.0.jar to the build path in Eclipse from
Project > Properties... > Java Build Path :
...and this warning appears in the Eclipse console:
More than one scala library found in the build path
(C:/Program Files/Eclipse/Indigo 3.7.2/configuration/org.eclipse.osgi/bundles/246/1/.cp/lib/scala-library.jar,
C:/spark/lib/spark-assembly-1.3.0-hadoop2.4.0.jar).
This is not an optimal configuration, try to limit to one Scala library in the build path.
FakeProjectName Unknown Scala Classpath Problem
Then I remove Scala Library [2.10.2] from the build path, and it still works. Except now this warning appears in the Eclipse console:
The version of scala library found in the build path is different from the one provided by scala IDE:
2.10.4. Expected: 2.10.2. Make sure you know what you are doing.
FakeProjectName Unknown Scala Classpath Problem
Is this a non-issue? Either way, how do I fix it?
This is often a non-issue, especially when the version difference is small, but there are no guarantees...
The problem is (as stated in the warning) that your project has two Scala libraries on the class path. One is explicitly configured as part of the project; this is version 2.10.2 and is shipped with the Scala IDE plugins. The other copy has version 2.10.4 and is included in the Spark jar.
One way to fix the problem is to install a different version of Scala IDE, that ships with 2.10.4. But this is not ideal. As noted here, Scala IDE requires every project to use the same library version:
http://scala-ide.org/docs/current-user-doc/gettingstarted/index.html#choosing-what-version-to-install
A better solution is to clean up the class path by replacing the Spark jar you are using. The one you have is an assembly jar, which means it includes every dependency used in the build that produced it. If you are using sbt or Maven, then you can remove the assembly jar and simply add Spark 1.3.0 and Hadoop 2.4.0 as dependencies of your project. Every other dependency will be pulled in during your build. If you're not using sbt or Maven yet, then perhaps give sbt a spin - it is really easy to set up a build.sbt file with a couple of library dependencies, and sbt has a degree of support for specifying which library version to use.
The easiest solution:
In Eclipse :
1. Project/ (righclick) Properties
2. Go to Scala Compiler
3. click Use Project Settings
4. set Scala Installation to a compatible version. Generally Fixed Scala Installation 2.XX.X (build-in)
5. Rebuild the project.
There are 2 types of Spark JAR files (just by looking at the Name):
- Name includes the word "assembly" and not "core" (has Scala inside)
- Name includes the word "core" and not "assembly" (no Scala inside).
You should include the "core" type in your Build Path via “Add External Jars”
(the version you need) since the Scala IDE already shoves one Scala for you.
Alternatively, you can just take advantage of the SBT and add the following
Dependency (again, pay attention to the versions you need):
libraryDependencies += "org.apache.spark" % "spark-core_2.11" % "2.1.0"
Then you should NOT include “forcefully” any spark JAR in the Build Path.
Happy sparking:
Zar
>
I work on an SBT multi-module scala project.
I use Idea to edit code and an external terminal with sbt ~compile for compiling.
I'm not very happy with this workflow.
Is there a better way ?
There are options to configure at some places, the doc is not very clear, so how to configure that :
in Build > Compiler > Scala compiler
in Languages > Scala
in Languages > Scala Compile Server
Do you configure some options on the scala compiler in idea ?
When and how do you compile (e.g. do you use make automatically in compiler settings) ?
Do you use idea or SBT for incrementality type
You can import multi-project SBT projects into scala via
File -> Import Project...
SBT project
When importing, make sure you select Use auto-import. This will keep your IntelliJ environment in sync as you change your SBT build files.
Under 13, at least, you may have to go into
File -> Project Structure
and delete some extraneous projects it ends up creating (it seems to create a project and project-build for me).
Once set up, building in IntelliJ will build via SBT, i.e. it's the same behavior as building via sbt compile.
Firing up the SBT console it reads :
[info] Building project AYLIEN 1.0 against Scala 2.8.1
[info] using MyProject with sbt 0.7.4 and Scala 2.7.7
How can I make it use MyProject with sbt 0.7.4 and Scala 2.8.1 ? Please pay attenetion that I'm not asking about the Scala version that is used to build my project (it is the 2.8.1 as you can see), but I rather want to make sbt use MyProject with Scala 2.8.1. Apparently sbt uses it's own scala version to work with project definition (MyProject here) which is different than one it uses to actually build the project! or perhaps I'm missing something ... ?
I can see your concern about SBT still using 2.7.7 internally, but it doesn't really matter since SBT downloads that version on its own. You do not have to install 2.7.7 or anything, just forget about it and pretend your environment is pure Scala 2.8.
The configuration file that holds the SBT version setting is: project/build.properties. The content looks like this:
project.organization=com.ab.web
project.name=cool_proj
sbt.version=0.7.4
project.version=1.0
build.scala.versions=2.8.0
project.initialize=false
When you want to move up to the next SBT version, just change 0.7.4 to that version and SBT will update itself. Eventually SBT will use some other Scala version internally, but this will not matter to the user.
SBT 0.7.* won't work with Scala 2.8.* for your project definition.
Mark Harrah is currently working on the next version of SBT which will work with 2.8.*. This means that you can't use any Scala features or functionality that was added after Scala 2.7.7 in your project definition or plugins. Your project itself is free to use 2.8.*.