I have just started trying to use Scala with IntelliJ. I created a new project as per the instructions in:
https://docs.scala-lang.org/getting-started-intellij-track/getting-started-with-scala-in-intellij.html
I installed scala 2.12.6 using Homebrew and selected that when creating my new Scala project in IntelliJ.
For some reason, under External Libraries, I have every jar inside the scala installation twice:
I created a hello world and when I try to run it, I get this error:
Error:scalac: Multiple 'scala-library*.jar' files (scala-library.jar, scala-library.jar) in Scala compiler classpath in Scala SDK scala-sdk-2.12.6
However inside the Scala libraries folder there is only one jar of each.
I'm not sure what I'm doing wrong here. I've tried other versions of Scala, but got the same results. I tried to delete one of the jars, and deleted the actual only copy of it and I had to reinstall scala.
#Zapatilla,
Follow this,
Click File --> Project Structure; Select Modules; Select Dependencies
You should see scala-sdk-2.12.6 there. Remove it by selecting it first and then clicking the "-" sign below.
Once done click the "+" button and select "2. Library --> Scala from SDK"; Select the appropriate version and hit Apply;Ok.
This should resolve it.
I just found the problem. When I right click on the library in the project explorer, I saw the paths for each jar file. It seems like in the scala installation by homebrew made in /usr/local/Cellar/scala/<version> there are two folders that contain the same jars:
/usr/local/Cellar/scala/<version>/idea/lib
and
/usr/local/Cellar/scala/<version>/libexec/lib
Since I was importing in IntelliJ this path /usr/local/Cellar/scala/<version>, all jars from both folders were imported, causing the duplication.
Solution is to import just one of those two options. I have now set up IntelliJ to just use as external libraries /usr/local/Cellar/scala/<version>/idea/lib and it seems to work!
I am using windows & intelliJ combination, I faced the same issue since i am new to scala, as usual i was searching in google and spend much time in resolving my issue.
Most of the suggestions are for linux based, please try the below, in my case it worked out.
1) Check your iml file and verify the orderEntry. By default if you download sbt, it would contain 2 set of libraries. I downloaded the SBT version 1.2.7, it by default contain 2 set of libraries. one with 2.12.0 and another with 2.12.7.
2) The project iml file of mine had with scala SDK 2.12.0 which was the reason for my issues, I edited that to change to 2.12.7 which automatically changed the order with 2.12.7 first and solved my issue.
This solved my problem.
Related
I've created a Play Framework program via Typesafe Activator (so it follows the template exactly).
I used sbteclipse-plugin version 3.0.0 to create an Eclipse project and imported that into Scala IDE 4.0.0. These are all the latest versions at the time of writing.
The Scala IDE definitely seems to support the Play Framework. It has syntax highlighting for the custom formats, including the routing file and templates. Yet, it doesn't seem to be able to find the views from the controllers. In particular, the call to views.html.index triggers an error: "object index is not a member of package views.html".
I tried enabling refreshing using native hooks or pooling as detailed here, but it had no affect.
I should note that while the code has been compiled in the command line (with activator ~run), it hasn't been compiled in Scala IDE, since I don't know how to (it doesn't seem to be documented anywhere).
What can I do to get rid of these false errors?
EDIT: After running activator clean ~run, I have another error: The project cannot be built until build path errors are resolved. There's no further details on what these build path errors are.
Update: Just upgrade to sbteclipse version 5.1.0 and everything should work out of the box. Also make sure you follow the Play documentation on how to set up Eclipse/ScalaIDE.
This is a known bug in sbteclipse, which probably will be fixed soon.
For now, you can add the following line to your build.sbt:
EclipseKeys.createSrc := EclipseCreateSrc.All
Kill the SBT console and run sbt eclipse again. That should add the following line to the .classpath file within your project folder as a workaround:
<classpathentry kind="src" path="target/scala-2.11/twirl/main"/>
Refresh your Eclipse project to pick up the change.
I had the same issue, also with Scala IDE 4.0.0 . I followed mkurz instuctions and they worked like a charm. But instead of changing the .classpath file in the project folder manually I used Eclipse interface:
In the top menu of the main window, click on Project and then on Properties.
In the Properties window, click on Java Build Path option (options list is on the left)
In the Source tab, click on Add Folder... button.
In the Source Folder Selection window, choose the target/scala-2.11/twirl/main folder, so it is included in the compilation path. Click Ok button.
Click Ok in the Properties window.
Now the project should compile just fine :) . With that I was able to finish the play setup example in Scala IDE website
I tried #mkurz solution first, but also ran into the same error as #matt. I became frustrated that I could not generate the eclipse project without having to go to the Eclipse project properties to manually fix the build errors. After some investigation, I discovered the solution that removed all errors entirely. Add this your build.sbt:
unmanagedSourceDirectories in Compile <+= twirlCompileTemplates.target
Or if that does not work for you, you could also use:
unmanagedSourceDirectories in Compile <+= target.zipWith(scalaBinaryVersion) { (b,v) => b / s"scala-$v/twirl/main" }
Good bye, build errors!
I got the same error message.
Are you using java8 as jre in eclipse?
After switching back from java8 to java7, everything worked fine again.
If, after following Mkurz' instructions (adding EclipseKeys.CreateSrc... ), your problems are not solved, click on Project -> Properties -> Java Build Path. Look at the source folders tab.
You may find a duplicate file folder named .../src_managed/main (Thanks Matt). If so, close the project. Remove ONE of the two ../src_managed/main entries from the .classpath file (located in the base of the activator/SBT project directory). Reopen and clean the project and you should be good to go.
For me, it turned out that installed JRE in the Scala IDE was openjdk, changed it to Oracle Java 8 and it worked.
I'm trying to use NetBeans 8.01 with Scala, and it can't find the "Scala Platform".
I'm using Windows8.1 x64. I follow this tutorial and also I have read this question but doesn't work.
I follow path tools-->Scala Platform and I have error: The specified folder not contain a Scala platform.
I try to add a new Platform but netbeans not find Scala platform.
Finally I try IntelliJ IDEA with scala and it's work.
So wonder if exist bug in netbeans or I must do something else? Can someone straighten me out?
Thank you
I found solution.
I add "-J-Dscala.home=C:\Program Files (x86)\scala" to the NetBeans/etc/netbeans.conf.
Now I can run an scala program.
However if you want to call scala program from java code in netbeans there are two ways
you must create maven project
package scala code to a jar and add this jar to Java project
Open the netbeans.conf file found in Netbeans/etc/
Find the section netbeans_default_options.
Add
-J-Dscala.home="C:\Program Files (x86)\scala"
in this section. Do not forget the " " around the path as spaces cannot be read.
I'm trying to get started with a quick Hello World application in Scala.
I'm using IntelliJ Ultimate 13.1.1. I've downloaded the Scala plugin. I've also downloaded the SBT plugin. The project SDK is Java 1.6.
I went ahead and created a new project. I selected SBT Project. The project is created fine. I notice that the src/main/* and src/test/* folders are created nicely.
When I right-click on the src/main/scala folder and try to create a new Scala object, there's no option to do so?! I tried to mark the directory as a sources root. Still, the issue persists. I'm given the option to create a Java file but not a Scala file.
What's going on?! I've been pulling my hair on this for the past two hours.
This is a bug in IntelliJ. Here is the answer to a bug report (#25058) I submitted:
Andrey Dernov (JetBrains Support)
Mar 26 19:43
Please see the respose from the developer:
Hi Dave, the problem was (mostly) because of the uppercase letter
(http://youtrack.jetbrains.com/issue/SCL-6853). You can either use
lowercase project name, or wait for a new plugin build that fixes the
issue. Thank you for the bug report!
You can get around it by explicitly editing the Run -> Edit Configurations and adding the class that you want to run. Set the main class and delete the $ (for the object).
I am new to intellij idea and I decided to shift because I found the scala plugin on eclipse to be annoyingly buggy.
But, intellij idea, which I have heard to be very good, looks difficult to use.
I looked through the getting started with scala plugin page but couldn't find documentation specific to the latest version of lightweight ide of intellij idea 11 for scala.
I have created a project and made a hello world object in scala but I am not able to run it.
On trying to run it, it shows the scala interpreter (type in expressions to get them evaluated).
I don't exactly understand what changes to make in the project structure to be able to run scala code. As of now, i added the jsdk to point to my $JAVA_HOME and the scala library is also added. The scala plugin is also working in that syntax highlighting etc is fine.
The intellij idea user interface is also not very friendly and I don't get how to run the code. What modules am I supposed to add? Also, does compiled scala code run with jvm?
I'll be grateful to anyone who helps out.. I have been putting off writing scala code because I am not able to find THE IDE.
EDIT: Thanks for all the help! I am now able to run a basic scala program. I am trying to add external jars. What is the equivalent of doing Project right click-> Configure Build Path -> adding external jar files in eclipse? I tried adding "dependencies " under modules tab in project structure. It's adding the jar files but somehow the classes in the jar files are not still recognised.
With the Scala plugin installed either
A. Create a new project and select the Scala facet in the creation phase. It will create the Scala library lib and Scala compiler lib and setup the facet for you
B. If you already have a project. Go to Project Structure -> Modules and right click the module and go Add facet and add a Scala facet. Now you need to add scala-library.jar as a library of the module and go into the Scala facet and point it to a library containing scala-compiler.jar
Some more information
this is what your module should look like under project settings
select the Scala facet and this is what you should see (Library name for the compiler is unimportant as long as it says (version xxx) next to the library name
these are the jar files in my scala-compiler lib
and these are the jar files in my scala-library lib
With everything setup like that you should be able to right click -> new Scala class (Select object from the dropdown) in a source directory and add
def main(args:Array[String]) {
println("Hello world")
}
then right click on the class and select Run Classnam.main() and IntelliJ will setup a run configuration for you.
Edit: I can see someone posted somewhat the same I want to say here. I hope this can give a few more in-depths hints, so I will post it anyway :-)
If you would like to run Scala native in IntelliJ (I shifted to IntelliJ and still can't get my hands down) you need to make sure a few things are in order. Most of this happens under File -> Project Structure which requires you to create a project (when you get a hang of it, it is much more logical than Eclipse -- and Netbeans for that matter). I am also assuming you have selected a jdk, but this can also be done in the Project Structure.
Now, to Scala:
Make sure you have the Scala plugin. Visit the Settings (File -> Settings; can also be found at the start-up screen) and locate 'Plugins' (for me it's nr. 8 from the bottom). Under "Browse Repositories" you should be able to search for "scala", find and install a plugin.
1 A. If no plugins pops up you are probably using a version of intellij where scala is not (yet) supported. If that happens you can go to the homepage for the plugin and download the nightly build.
Import Scala as a library in File -> Project Structure -> Global Libraries. Click the plus sign, select Java (Scala is a Java-lib), browse to your scala-dir (which can be downloaded here: http://plugins.intellij.net/plugin/?id=1347) and select the lib directory. Press ok and you should see the library popping up on the list.
Make sure the facet (Scala framework) is in place. Goto File -> Project Structure -> Facets. Click on the plus-sign and find Scala. A sublink should appear (if not double-click the Scala link). Clicking the sublink make sure you have selected a compiler before continuing. This should be provided by the modules selected before. I normally use FSC (Fast Scala Compiler) but it's probably a good idea to test the basic settings before experimenting.
Make sure the Scala Module is in place. In Project Structure -> Modules click on the module you want to compile in scala and click the plus icon above and select Scala. Again be sure to select a compiler library.
If you want to, setup configurations for the compiler under the facet
Use sbt with sbt-idea plugin to generate idea project files for complex projects.
Or
For simple projects.
Add scala nature to the project, and you can right click and run any file extending App.
A good walk-through on how to set up a Scala project in Intellij is located here:
http://sonyarouje.com/2011/03/18/running-scala-in-intellij-idea-10/
I recently gave up trying to use Scala in Eclipse (basic stuff like completion doesn't work). So now I'm trying IntelliJ. I'm not getting very far.
I've been able to edit programs (within syntax highlighting and completion... yay!). But I'm unable to run even the simplest "Hello World". This was the original error:
Scala signature Predef has wrong version
Expected 5.0
found: 4.1 in .... scala-library.jar
But that was yesterday with IDEA 9.0.1. See below...
UPDATE
Today I uninstalled IntelliJ 9.0.1, and installed 9.0.2 Early Availability, with the 4/14 stable version of the Scala plug-in.
Then I setup a project from scratch through the wizards:
new project from scratch
JDK is 1.6.u20
accept the default (project) instead of global / module
accept the download of Scala 2.8.0beta1 into project's lib folder
Created a new class:
object hello {
def main(args: Array[String]) {
println("hello: " + args);
}
}
For my efforts, I now have a brand-new error :)
Here it is:
Scalac internal error: class java.lang.ClassNotFoundException [java.net.URLClassLoader$1.run(URLClassLoader.java:202), java.security.AccessController.doPrivileged(Native Method), java.net.URLClassLoader.findClass(URLClassLoader.java:190), java.lang.ClassLoader.loadClass(ClassLoader.java:307), sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301), java.lang.ClassLoader.loadClass(ClassLoader.java:248), java.lang.Class.forName0(Native Method), java.lang.Class.forName(Class.java:169), org.jetbrains.plugins.scala.compiler.rt.ScalacRunner.main(ScalacRunner.java:72)]
FINAL UPDATE
I uninstalled 9.0.2 EA and reinstalled 9.0.1, but this time went with the 2.7.3 version of Scala rather than the default 2.7.6, because 2.7.3 is the one shown in the screen-shots at the IntelliJ website (I guess the screen-shots prove that they actually tested this version!). Now everything works!!!
I have encountered the same scalac error when trying to run a Scala project in Intellij Idea 9.0.2 and I've managed to find a solution by chance :). These are the steps I took in creating the project and running it.
I have created a Scala project in Intellij Idea 9.0.2 final (it was released today). I have installed the Scala plugin, restarted the IDE and created a new Scala project (with the name "TestScala") with scala-2.8.0.Beta1 as project library. Once the project is created and the scala libraries downloaded, I have created a Test.scala file with the following content:
object Test {
def main(args:Array[String]){
println("hello")
}
}
After that, I created a launch configuration ("Edit Configurations"), choosing the "Application" template. I set as main class Test and choose the project name ("TestScala") in the "Use classpath and JDK of module" combo box. When I run the configuration I get the same error as you reported ("Scalac internal error: class java.lang.ClassNotFoundException") .
Now comes the freaky part :). I right click on the project, choose "Module Settings", have a look on all settings but I don't change anything . Click "apply" and "ok", try to run configuration again and it works :) .
I use Intellij Idea 9.0.2 the final release (build 95-66); Ubuntu 9.10 and JDK 1.6.0_18. I also have to mention that I had a JDK configured in Intellij, otherwise there is an extra step to configure it.
UPDATE:
When checking the setting of the module, one needs to click on the Module->Scala and Facets->Scala (expand it and click on Scala(ProjectName)) . Both of these settings are about the scala compiler and scala library location. I would guess these values are not properly set when the project is created but are saved once the user touches them and saves the settings.
To answer your question, it's difficult to get a working IDE for Scala for two reasons:
(a) Scala is only just beginning to reach a wide audience and
(b) due to (a), there is no business case for spending time on a Scala IDE.
Also, if you are old enough to cast your mind back and young enough to still remember, you would know that for the first five or more years of Java, we were stuck with okay-ish tools like JBuilder that did little more than compile your code when you said so - no error highlighting, no auto-importing, and the word refactoring didn't even exist. If you want to pioneer, you need to be prepared to cut some of the road yourself, or at least bush-bash.
I know it won't help you, but I have successfully used IDEA for Scala on Linux, Mac and Windows. I typically have the Scala SDK installed somewhere locally and point IDEA at that rather than using the 'download' option.
Presently, I am mostly using an EAP version of IDEA 9 on Mac OS X with Scala 2.8.0.Beta1-RC5 and it's working well (except that fsc doesn't seem to worked with mixed sources).
You could try your luck over at the IDEA Scala Plugin Discussion Forum, though I haven't had a great lot of responses to my own postings there.
Installing the plug-in is prerequisite one.
The next thing you should do is define a library (global or project-specific; I use global) that holds the Scala library and compiler JAR files (at a minimum, that's scala-compiler.jar and scala-library.jar). Adding source JARs and a documentation JAR or URLs is a good idea, too. Then make this library a dependency of any modules in your project that include Scala code.
Lastly, find the Scala facets in those modules and de-select both check-boxes there.
I just did a fresh install and had exactly this same problem myself.
It turned out that, because I had created the file in the root package, IDEA had added a package statement at the top with naming a package. I assume that this then got compiled as "package object Main" - valid syntax in 2.8? Anyway, I deleted the line that said package and it all worked fine.
I had the same problem yesterday while trying to set it up. Solution is pretty simple, you just have to set scala somewhere in project settings.
You are mixing code compiled with two different Scala versions.
I use Netbeans to write scala programs. So far it works very well with my codes. You can try the plugin here: http://wiki.netbeans.org/Scala68v1.
I was getting this error and also had to right click on the project and "Open Module Settings". However, it was more than just hitting apply. I had to make sure that my Content Root was correct for each project. For some reason, there were some incorrect Source and Test Folders.
My project uses maven as the main build tool and importing the project into Intellij is probably what created these incorrect settings.
I had similar problem, following this blog post instructions solved the problem for me