Before 1.14 I could simply click debug button in Eclipse and it would run Minecraft with my mod, in this case I could do step debugging, pause everything, view threads and etc. But in new version to run Minecraft with my mod I need to run gradlew runClient. It runs perfectly but I can't debug it. Maybe I need to attach Minecraft process to Java debugger somehow.

I use Eclipse (2019-12), and I am able to run/debug my project within the IDE without having to manually run gradlew tasks.

How did you setup your project?

 

I know you can import the gradle project into the IDE and run the tasks from there, but I still do things from the commandline, because I'm old, so I just ran gradlew eclipse and gradlew genEclipseRuns in my mod project folder to get things setup (I actually, for whatever unknown reason, have to run them twice to get the MC/Forge sources to attach in the IDE properly, no idea why or how, but running once, I don't get sources, if I run them twice, I have sources lol). Not sure how you do it, or if a difference in project setup would even cause that to happen.