How do I debug a Java app running in a Docker container in IntelliJ IDEA 2018.2?

Question

I have a Java app that I'm attempting to debug inside of (because a particular error only happens when the app is run from inside Docker , which is fun ), but I can't figure out how to get IntelliJ to attach for debugging.

I have the Docker Integration plugin installed, but when I go to run my container, the deploy log has a line that says Cannot retrieve debug connection: Debug port not specified . Google told me that I needed to add a debugPort entry to my workspace.xml file, but when I did that , my Run/Debug configuration complained that "Debug port forwarding not found". Clicking "Fix" resulted in a container_settings.json file being created, which IntelliJ immediately informed me wasn't supported in 2017.3+, and that i should use command line options instead. However, I have no idea what those command line options should be.

When I tried specifying the forwarding port in the Run/Debug configuration, the deploy log ended with Cannot retrieve debug connection: java.net.MalformedURLException: unknown protocol: unix , which makes no freaking sense.

Help!

Answer 1

You can even use dcevm / HotswapAgent in dockerized application and modify code/resorces without restart. Look at this project https://github.com/HotswapProjects/hotswap-docklands