How to Fix IntelliJ IDEA High CPU Usage: Config Tweaks and JDK Tips

Background

After running code, IntelliJ IDEA became extremely sluggish, even after cracking the trial version. The CPU usage remained high, prompting a search for solutions.

Modify idea.exe.vmoptions

Edited the configuration file located in the bin directory. The project opened slightly faster, but CPU usage stayed high.

Turn Off Code Inspections

Navigate to Settings → Editor → Inspections and uncheck unnecessary inspections. This had little effect on performance.

Uninstall Unnecessary Plugins

Removed extra plugins, but as a beginner the impact was minimal and the step was skipped.

Select the Appropriate JDK Version

Used the official JDK 1.8 instead of the bundled version. This resolved the issue.

Identify the Real Cause: Infinite Loop

Observed that a while(true) loop in multithreaded code caused CPU usage to spike to over 80%. Added a flag to break the loop when ticket < 0, which solved the problem.

After applying these changes, IDEA’s resource consumption returned to normal.

Conclusion

Resolving the performance issue not only improved the development experience but also reinforced the importance of diagnosing root causes, such as infinite loops, rather than relying solely on IDE settings.