RUN simply stopped working for one single project which previously worked fine (no changes to configuration)

Please share a sample project to reproduce.

Did you try deleting IDE folders to start from scratch (https://intellij-support.jetbrains.com/hc/articles/206544519)?

I have few projects with exact same configuration and the issue does not occur for them... I've reinstalled Idea completely and the issue persists which makes no sense to me at all..

Reinstalling IntelliJ IDEA doesn't remove IDE folders mentioned in https://intellij-support.jetbrains.com/hc/articles/206544519 by default. Double check it.

Compare the run configuration files in the projects where it works and where it doesn't work: http://stackoverflow.com/a/3136255/104891.

Sample project can be any Spring Boot hello world. I've removed configuration folders before installation but either way why does installer even asks whether to reuse previous configuration or not ?

So that you can import the settings from the previous version after updating.

Gotta say its near impossible to compare some idea configuration files..

Found the issue - Gradle plugin in version 181.5281.24, looks like on my previous installation it also updated in "Stealth" mode or i didn't notice it... Disabling Gradle plugin fixed my problem, too bad at the cost of well not being able to use Gradle...

No idea why exactly Gradle plugin conflicts with this one particular multimodule project.

Is it gradle-based project? Could you reproduce the issue and attach the project with the `.idea` folder included to recreate the issue? Please also add idea logs.

Weirdest part its not a gradle-based project but maven one. If i get a moment ill do that.

Add 2 hours of lost life time from my side. I have to keep gradle plugin deactivated for my maven projects.

Build 181.5281.24, JRE 1.8.0_152-release-1136-b39 amd64.

@Bruno Eberhard could you please provide an example project if possible?

@Petr I would like to. But it only happens for our complex projects. A simple 'hello world' does work. I keep an eye on it maybe I stumble upon the trigger of the problem.

I can confirm I had the same issue and disabling the gradle plugin Version: 181.4203.550 also fixed it (even though my project is not even a gradle one but a normal spring boot maven project) 

@Plosson Is it reproducible with new simple project?

Easy to reproduce adding a dependency to Javalin library for lightweight rest server.

After adding it to my project, when pressing run it does nothing and the run button is disabled..

I added Javalin dependency to my sample Maven project, but run button works fine.

Is the gradle plugin disabled or enabled?

What version of Intellij are you using? What version of the gradle plugin are you using?

I checked on 2018.3 EAP with Gradle plugin enabled.

I have also had this happen with maven projects. Currently on 2018.1.3 and Gradle plugin 181.4892.42. I don't know how to reproduce it because everything works fine until it doesn't.

Hello Matt,

Could you please check the issue with 2018.3 EAP?

Same problem here. I recreate the project and it works until it stops working again. I then have to recreate it again...

Any way to help debug? It's a big problem for me.

Please report at https://youtrack.jetbrains.com/issues/IDEA with the logs attached (https://intellij-support.jetbrains.com/hc/articles/207241085). Also attach .idea directory contents from the project.

Hello,

I had the same problem. At once run button stop working, it was just doing nothing and after first click was disabled (the same with debug button as well as run icon in the main class/method). I've tried everything with disabling cache and updating Intellij too. As you mentioned above disabling the gradle plugin worked (it's maven project...). However when I finally was able to run my run configuration I saw the error : 

"Error running '...Application': Command line is too long. In order to reduce its length classpath file can be used. Would you like to enable classpath file mode for all run configurations of your project?"

Maybe it was the main reason why Intellij was not able to run project, but it was somehow hidden? Anyway it's very strange why gradle plugin has any influence to this 

Regards

@Pawel Matysek may be related https://youtrack.jetbrains.com/issue/IDEA-180659#focus=streamItem-27-2542804-0-0

@Pawel Thank for the help. I'll try to see if any of the plugins I use could be causing the problem for me. I don't use gradle.

I forgot to mention I am using Goland IDE.

In my situation, before upgrading to Springboot 2.0 all the Junit tests worked fine, then after upgrading it simply would not run. Click the run button does nothing, no logs either.

Disabling the Gradle plugin resolved my issue. However, preferably someone can find the root cause, in case I need to use Gradle in the future.

Thank you Daniel Hajduk for posting the solution to disable Gradle plugin.

I've lost 4 hours on this. My project is Spring Boot 2 (maven) using IntelliJ Ultimate 2018.1

Had the same exact issue described by OP, my solution was also to disable gradle.

My project is a Maven project.
This project was working a month ago.
Other projects with same config were/are working fine.

Thanks Daniel for posting your solution.

Edit: Only difference I can tell is that the project that stopped working was multi-module.

I ran into this issue as well. disabling the gradle plugin worked (it's maven project...).

Thanks for posting your solution. 

Anyone having this issue - it would be of much help to have a sample project where it is reproducible. Thank you.