Scala import cannot be resolved in Java project

I am working on a Java Play 2.6 project and wanted to switch from eclipse (ScalaIDE) to VSCode (because I use VSCode for everything else and I largely prefer to work with it rather than eclipse).

In Eclipse, I have no problem importing a Scala source ( scala.collection.Seq ) but in VScode, opening the same Eclipse project and having no problem with all other external librairies, it cannot resolve the scala.collection.Seq import. (more precisely it's the scala.collection import ).

When compiling my project in the console using sbt, I have no problem.
Also Eclipse is able to resolve that import. Maybe it has to do with the "Scala library container" exlipse plugins of ScalaIDE

Environment

• Linux Ubuntu 16.04
• JDK version: 1.8
• Visual Studio Code version: 1.23.1
• Java extension version: Language support for Java(TM) by Red Hat 0.26.0

Steps To Reproduce

1. Create a Java play project using sbt
2. Import it in ScalaIDE
3. Create a class that imports scala.collection.Seq
4. Open the project in VSCode.

Logs : No errors in the logs.

Inizia riproducendo il problema con un progetto Java Play 2.6 creato con sbt, quindi confronta la risoluzione delle dipendenze di VSCode con le build funzionanti di Eclipse e della console. Il problema è risolto quando il progetto Java risolve l'import scala.collection.Seq in VSCode senza errori.