decompiles jar package using Intellij's build in Fernflower decompiler and attaches decompiled sources to project. decompiled sources are saved in folder 'decompiled' which is created in the project directory. to use it, just right click on jar file and select "Decompile And Attach" action
SEC-fsq/decompile-and-attach
(Intellij) decompiles jar library and attaches sources to current project
JavaMIT