I posted a similar question regarding gradle but this question is without gradle or maven.
I can not get Kotlin working properly using Eclipse IDE. This works great using IntelliJ, however many developers still use Eclipse. I have installed the Kotlin Eclipse plugin and does not work. I have downloaded the Kotlin standard library and runtime library and added them into the project. Still not working. All I get in eclipse when I have Java and Kotlin is cannot be resolve to a specified type.
I'm not using maven or gradle because I couldn't get it working with those two either.
If I mix Java and Kotlin in the same source folder I get this error.
"The type error.NonExistentClass cannot be resolved. It is indirectly referenced from required .class files"
I'm using Eclipse Neon. If anyone can help me that would be awesome, I've been trying for quite some time now and not getting anywhere. :(
Add Kotlin Nature fixes the issue. Click on your project and Configure
Kotlin -> Add Kotlin nature
This partially fixes the issue, though eclipse plugin is still buggy and auto import function still doesn't work for me.
If you're having any issue, make sure you have kotlin_bin folder added in your project. Also make sure that ALL kotlin files have the correct package name sometimes when you rename packages or move files around kotlin classes may not get updated.
Got similar issue solved by adding a new Kotlin file to a Kotlin/Java mixed project. Adding the file caused Eclipse 2018-09 (4.9.0) to add kotlin-stdlib.jar and kotlin-reflect.jar to classpath and everything started working.
Add Kotlin Nature fixes the issue. Click on your project and Configure Kotlin -> Add Kotlin nature
As of the current Eclipse version (2019-09):
You can't add Kotlin to a Java project, but you can add Java to a Kotlin project.
The procedure to accomplish a mixed Kotlin/Java project was roughly:
Install Kotlin plug-in
Create empty Kotlin project
Move the Java code into the Kotlin project
Delete the original project
Fix project references
I'm working on a project with Spring Boot and Kotlin (some controllers/mappers/classes in Java and others in Kotlin) and after trying a lot of approaches, the only that worked was to use Eclipse 03-2020 and Kotlin Plugin for Eclipse V0.8.19.
https://dl.bintray.com/jetbrains/kotlin/eclipse-plugin/0.8.19/
Before everything, close your project and uninstall the previous version of Kotlin Plugin for Eclipse.
Go to Help/Install New Software.
Copy the link of Eclipse Plugin and continue with the installation (do not forget to check all the options to install).
After the installation restart the IDE and try compile again.
If your project was like mine, it has .kt files in /src/main/kotlin, some missing references in Java. I tried compiling them but nothing worked. It turns out that my project didn't have an Eclipse Source Folder associated with the kotlin code. There were the usual ones for "src/main/java", "src/main/resources" but not one for "src/main/kotlin".
So, I created a source folder for the kotlin files.
Right click the project
New "Source Folder"
Specify folder name: "/src/main/kotlin"
This doesn't create anything in the file system but just creates a logical container for Eclipse to work with the contents. In this case, Eclipse recognized the .kt files, compiled them and all the missing references issues all cleared up.
Related
Situation: I have a Java file in my project that uses the features of the iTextPDF library. The project compiles properly. I use JDK 1.7, Tomcat 7.45 and Eclipse Neon.3 Release (4.6.3).
Problem: While starting the server via Eclipse, I get an error:
java.lang.ClassNotFoundException: com.itextpdf.text.Element
What I've tried so far:
Ensured that only 1 version of iTextPdf 5.4.jar is available in the entire project. It's there in WEB-INF/lib folder. It's not there in any of the externally referenced libraries.
I updated my Eclipse.
Any help will be greatly appreciated.
Well, as a starting point- try and expanding the JAR, and see if you can search for or manually find com.itextpdf.text.Element class.
if it's not found there, you know there's nothing wrong with your eclipse or project settings, and nothing wrong with your jar imports.
You should then determine between 3 options:
Is the JAR even on the classpath? it's possible everything is present there, but the project does not even consider looking in it.
Should this class be in the JAR? is it available on other versions of this JAR?
Is this class neccesasry for you application? why is eclipse looking for it, where in the code it is referecened? can you live without it? or, can you manullay replace it with a class file you can find online? (this will take some debug time, and some more research on your part)
java version "10.0.1"
Eclipse jee 2018-2019
Windows 10
I'm just trying to add a simple file to my package. After adding the file, I get the below error.
The project was not built since its build path is incomplete. Cannot
find the class file for groovy.lang.GroovyObject. Fix the build path
then try building this project.
Pretty much all posts say to delete the JRE System Library and add it again, do a refresh, clean restart. I did this, but I'm still getting a build path error.
I followed these instructions. Other forums on stack say similar things.
http://hemant-vikram.blogspot.com/2012/07/eclipse-build-error-project-was-not_12.html
New to Eclipse and Groovy. I just want to follow the tutorial :|
If you have added references to Groovy types, you can add Groovy libraries to your classpath by right-clicking on your project and choosing "Add Groovy Libraries to classpath". This assumes you have Groovy Development Tools installed.
Or you can add "org.codehaus.groovy:groovy-all" through Ivy, Maven or Gradle if you are using one of those for dependency management.
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.
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 created a new PLAYN project based on the "Generating a skeleton project with Eclipse" instructions on the wiki
( found here: http://code.google.com/p/playn/wiki/GettingStarted#Generating_a_skeleton_project_with_Eclipse )
Everything was set up correctly but Eclipse doesn't recognize it as a java project so I lose the syntax checking, content assist, etc (I get run-time error dialog box when content assist tries to help) for java.
I get "compilation unit is not on the build path of a java project" followed by "The 'org.eclipse.mylyn.java.ui.javaAllCompletionProposalComputer' proposal computer from the 'org.eclipse.mylyn.java.ui' plug-in did not complete normally...".
Did I miss a step? Is there a way to add it to the project?
I tried editing the .project to add a java nature but that really messed up the project structure constructed by maven. (based on How do Java and Maven builders work together in eclipse?)
I tried adding a java builder to the project properties and looked adding a plug-in dependency in Maven but couldn't figure that out (I'm still learning Maven).
thanks.
Make sure you are writing code in the [project-name]-core Eclipse project rather than the [project-name] Eclipse project.
Searching around internet I found several reasons for this error. In my case the problem was that the project's nature was not Java.
To fix that:
close the project
edit file .project on project's root
Add the following line to section:
org.eclipse.jdt.core.javanature
Done. Open your project and code assist works correctly now.