java.lang.NoClassDefFoundError: org/apache/tools/ant/util/ReaderInputStream vaadin+gradle+intelliJ

Question

I have been working fine with Vaadin + Gradle + IntelliJ until yesterday night when I introduced SLF4J(logback) logging to my application. Since then I can't make my project anymore due to classDefFoundError of org/apache/tools/ant/util/ReaderInputStream.

I can't link it with any transitive dependency of any contained jar in application, but even if I remove SLF4J libraries I still can't make my application, so I am wondering what changed?

I am using vaadin gradle plugin 0.9.5 and gradle 2.2.1. Has anyone ever encountered this problem? I was reading another post where someone had the same issue, but the solution he proposed is not valid to my application. He proposed to comment some of the lines in vaadin.gradle, which my application doesn't have.

Answer 1

Try

File > Invalidate Caches / Restart...

Answer 2

File > Invalidate Caches / Restart... nor did git clean -dfx. Here is what I had to do:

1. Close IntelliJ
2. IMPORTANT: Make sure you have everything commited you care about (you're about to clean your working copy)
3. Run git clean -dfx to clean your working copy
4. Run IntelliJ
5. Select Import Project
6. Navigate to the directory containing your project
7. The select Import project from external model and select Gradle
8. Press Next
9. Make sure the settings on the next page look ok then press Finish
10. The build should now hopefully work

Answer 3

I deleted the .idea folder and that worked for me.

Answer 4

File > Invalidate Caches / Restart... option didn't work for me, but

sudo git clean -dfx worked fine

Answer 5

remove .idea and invalidating caches worked for me.

1. rm -r .idea/ in command line
2. in Intellij GUI File > Invalidate Caches / Restart...