## 📜 [Spring Boot] Why My `log.trace()` and `log.debug()` Weren’t Showing – And How I Fixed It

📜 [Spring Boot] Why My log.trace() and log.debug() Weren’t Showing – And How I Fixed It

While testing my Spring Boot app, I wanted to log messages at different levels using Lombok’s @Slf4j. But something was off...

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🧪 What I Did

I created a class that logs messages when the app starts:

@Slf4j
@Service
public class LogginRunner implements ApplicationRunner {
	@Override
	public void run(ApplicationArguments args) throws Exception {
		log.trace("TRACE 로그 메세지");
		log.debug("DEBUG 로그 메세지");
		log.info("INFO 로그 메세지");
		log.warn("WARN 로그 메세지");
		log.error("ERROR 로그 메세지");
	}
}

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❓ What Happened?

Only these showed in the console:

INFO 로그 메세지  
WARN 로그 메세지  
ERROR 로그 메세지

But my TRACE and DEBUG logs were completely missing.

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💡 The Reason

Spring Boot sets the default log level to INFO.
This means anything below that (TRACE, DEBUG) won’t show up unless you manually allow them.

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🛠️ The Fix

I updated my application.properties:

logging.level.ruby.paper=trace

🔍 This tells Spring:

"Show all logs (even the very detailed ones) for anything under the ruby.paper package."

After restarting, all log levels appeared, including TRACE and DEBUG.

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🔁 Bonus Tip: Set Level by Category

You can also target different packages or globally:

# For everything
logging.level.root=debug

# For a specific package
logging.level.com.example.service=debug

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✅ Summary

Problem	Fix
TRACE and DEBUG not showing	Add logging.level.package=trace in application.properties
Default log level is too high	Spring Boot’s default is INFO, so lower ones are hidden

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📘 Final Thought

Logging levels help you see just the right amount of info at the right time. If something isn’t showing — check your logging level first!