There is no dedicated Checker Framework plugin for IntelliJ IDEA (yet), but there is a plugin that provides LSP support for IDEA, LSP Support, which makes it possible to integrate the Checker Framework Language Server.
After installing LSP Support and downloading the Checker Framework Language
Server and
Checker Framework to your system,
go to Preferences - Languages & Frameworks - Language Server Protocol - Server
Definitions, then choose “Raw command”, and add the extension java. A sample
command that will run the Nullness Checker is:
java \
-cp /path/to/languageserver.jar:/path/to/checker-framework/checker/dist/checker.jar \
org.checkerframework.languageserver.ServerMain \
--frameworkPath /path/to/checker-framework \
--checkers org.checkerframework.checker.nullness.NullnessChecker
After this, red squiggle lines will be drawn under errors detected by the Nullness Checker. For other options, please refer to the documentation of the language server.