Could not find or load main class in scala in intellij IDE

Question

I have searched for this error, but the answers were for Java, but my case is Scala. I am trying to run this project in IntelliJ IDE sentimenAnalysis, but it throws an error. This is also the structure of the project. Class Not found

Update 1 According to answers, Adding $ at the end of the name of search class

Update 2 after adding sbt task:

Update 3 My problem was resolved by importing the project, instead of getting it directly from GitHub, probably the manual configuration that Mike Allen said could resolve the problem, but I couldn't successfully apply that.

score 44 · Answer 1 · edited Jan 06 '23 at 04:20

44

My problem was resolved when I marked "src" folder as sources root.
Right-click on (folder) src -> Mark Directory as -> Sources Root

edited Jan 06 '23 at 04:20

blackraven

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answered May 06 '18 at 23:02

Laura Corssac

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3

This worked for me to remove the error but then it started showing different error of is already defined as . Then I followed https://stackoverflow.com/a/27352057/3209170 and removed src from sources root and it worked. Idk why but if someone is beginner and stuck, try this. – HBB20 Oct 10 '18 at 12:54
Worked for me. 1st remove scala folder as source root, 2nd make src folder as source root, run build – Remis Haroon - رامز Jun 19 '20 at 10:28

score 21 · Accepted Answer · answered May 24 '17 at 17:08

21

Probably you imported project somehow wrong. I see scala folder is not highlighted as sources. Usually, you don't even need to setup Run configuration manually for Scala SBT project. Do you have Scala and SBT Plugins in your IDE?

You should open SBT projects through "Import project" and choose "build.sbt" file. I would also recommend enabling auto-import to install all of the dependicies.

That's how it look for me:

If you still wanna make it manually your configuration should work. That's my Run configuration that works:

answered May 24 '17 at 17:08

SeriousDron

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thanks for your answer, Actually I open the project throgh github, is it okay to do so? – sariii May 24 '17 at 17:17
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So your project is misconfigured. You probably can fix it manually. But much easier is just import it as I said from path you have cloned it – SeriousDron May 24 '17 at 17:22
but I dont have "import project" in the menu file – sariii May 24 '17 at 17:25
Close your current project. You'll have it on IntelliJ IDEA splash window – SeriousDron May 24 '17 at 17:30
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It ssems strange when I am importing it works fine, when I just use the github it cant bring the configuration and raises errors, anyway many thanks for your time help and effort – sariii May 24 '17 at 20:54
one more question, if you runned the search without any error? cause I am getting null exception error, may I ask you to share your information if you know? thanks :) – sariii May 24 '17 at 21:02
Sorry, I don't know. You can create a separate question with full error description, logs, etc, then I hope somebody will help you. – SeriousDron May 25 '17 at 21:16
when you directly import scala-project from github, intellij doesn't import it correctly.. you can do git pull and then open project in intellij, that way it always works.. – Shailesh Dec 14 '17 at 08:33
simply building the intellij project worked for me. – Tukaram Bhosale Jun 02 '19 at 14:05

score 7 · Answer 3 · answered May 11 '18 at 17:55

7

You will get this error if you tried to open the project and imported it incorrectly. I would open the project like this in Intellij:

File>New> Project from Existing Source>(select) Import project from external model>
(select)sbt

click Next>Finish

answered May 11 '18 at 17:55

alltej

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score 6 · Answer 4 · answered Aug 21 '20 at 10:32

6

To fix this issue in my project I invalidated caches and restarted:

answered Aug 21 '20 at 10:32

Adrian

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Surprisingly this worked for me, make sure to run built.sbt sync after the indexing completes. – Pavan_Obj Jul 29 '21 at 22:13

score 3 · Answer 5 · answered Jan 11 '18 at 08:59

In my case the object in the object MyObject extends App was nested, if you have it unested meaning in your scala file it's not under any other object it made it work.

Netsted caused this error in intellij:

object External {
  object MyMain extends App // Could not find or load main class in scala in intellij IDE

}

While the below unested worked:

object External { }
object MyMain extends App // Worked!

score 2 · Answer 6 · answered Aug 03 '18 at 02:50

2

Hi I solved this problem by defining the class in src package under main and by setting up the configuration as default.

answered Aug 03 '18 at 02:50

Tutu Kumari

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score 1 · Answer 7 · answered Jul 31 '17 at 12:27

Create a new project and make sure SBT is proper loaded along with Scala Library. This happens with many times, bad internet connection or failure of Scala library/SBT loading might be some of the reasons. Best of Luck for Next Project, Happy Developers & Coders.

score 0 · Answer 8 · answered May 29 '22 at 20:36

0

Had a similar problem with latest Intellij IDEA build (2022.1.1) and scala 3.1.2 - both sbt and Intellij scala projects. For me the solution was to use non-ascii path.

answered May 29 '22 at 20:36

kwojcikowski

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score 0 · Answer 9 · answered Jan 30 '23 at 18:55

@SeriousDron answer helped me with my problem. You need to make sure you have Scala language installed in IntelliJ. You can do this by going to Settings > Plugins > search for "Scala". Now, it will automatically pick up your .sbt file and project.

score -1 · Answer 10 · edited Jul 03 '20 at 11:28

-1

I met the same issue, please check the whole execute command and check the configuration, make sure the compiled files path is correctly configured. refer to my screenshot:

edited Jul 03 '20 at 11:28

Dharman

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answered Jul 03 '20 at 09:06

NutHu

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Could not find or load main class in scala in intellij IDE

10 Answers10