Why so red? IntelliJ seems to think every declaration/method cannot be found/resolved
Seeing red in IntelliJ? Fix it quickly by:
- Clearing Cache:
File>Invalidate Caches / Restart>Invalidate and Restart. Freshens up the IDE's index. - Reimporting Project: From the Welcome Screen,
Import Projectand select your existing project's build file (pom.xmlfor Maven,build.gradlefor Gradle). - Setting SDK:
File>Project Structure>Project. Confirm the Project SDK and language level are in sync with your codebase. - Rebuilding Project: Hit
Build>Rebuild Projectto freshly compile everything.
Remember, the Invalidate Caches option is a great first step—it often resolves the red plague.
Troubleshoot like a BOSS
Still seeing red? Let's roll up our sleeves and dig deeper:
Kick Maven/Gradle into gear
- Reimport Maven Projects:
View>Tool Windows>Maven>Reimport All Maven Projects. This tells Maven to freshen up. - Sync Gradle:
View>Tool Windows>Gradle>Refresh All Gradle Projects. This is basically saying "Hey Gradle, get your act together!"
Grapple with the External Forces
Let's be honest, sometimes IntelliJ gets confused by the outside world. If dependencies are tweaked outside IntelliJ, it's a good idea to reimport the project.
Sync, because two is better than one
File > Synchronize forces IntelliJ to sync with the file system and reflect any lurking changes.
Healing the IDE
If the IDE went rogue and the settings seem corrupted then:
- Repair IDE:
Help>Repair IDEis like a factory reset—it restores default settings and wipes any inconsistencies.
Dealing with sticky reds
When your code is as stubborn as a mule and refuses to turn green, try these:
JDK mismatch - Problem or identity crisis?
IntelliJ must use a JDK that syncs with your project. Check JDK in:
- Project Structure:
File>Project Structure>SDKs. SDLs should point to the correct JDK and the paths should sayI'm not lost!
Plugin pandemonium
You love Lombok, IntelliJ loves you—but only with the plugin:
- Plugins update:
File>Settings>Plugins. Be sure that plugins like Lombok are installed, enabled, and not in a cyber hibernation.
Environmental impact
Changed your environment? Remember to restart IntelliJ:
- Restart: A reboot can help IntelliJ soak in the new environment variables.
When the going gets tough, the tough get deleting
Things looking bleak? Fear not:
- Delete .idea Folder: The
.ideafolder might be messed up. Deleting it can be the silver bullet (Alert: Only for the brave at heart).
Afterward, redo your Maven/Gradle imports and JDK settings. Breathe in, breathe out, open IntelliJ.
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