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Explanation

Logging helps developers monitor application behavior, debug issues, and track important events during execution. Spring Boot uses SLF4J as the logging API and Logback as the default logging implementation, providing a flexible and production-ready logging solution.

Code:

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

private static final Logger logger =
    LoggerFactory.getLogger(StudentService.class);

Explanation

SLF4J provides different logging methods based on message severity. Developers can log debug information, application flow, warnings, and errors, making it easier to troubleshoot problems in development and production environments.

Code:

logger.trace("Trace message");
logger.debug("Debug message");
logger.info("Student created successfully");
logger.warn("Invalid request received");
logger.error("Database connection failed");

Explanation

Log levels determine which messages are recorded. TRACE provides detailed diagnostics, DEBUG is useful during development, INFO logs normal application events, WARN highlights potential issues, and ERROR records failures that require immediate attention.

Code:

TRACE
DEBUG
INFO
WARN
ERROR

Explanation

Spring Boot allows log levels to be configured through application.properties. Developers can set different logging levels globally or for specific packages, reducing unnecessary log output while capturing important application events.

Code:

logging.level.root=INFO
logging.level.com.example.service=DEBUG
logging.level.org.springframework=WARN

Explanation

Logback is Spring Boot's default logging framework. By creating a logback-spring.xml file, developers can customize log formats, write logs to files, configure rolling log files, and define separate appenders for console and file output.

Code:

<configuration>
    <appender name="FILE"
        class="ch.qos.logback.core.FileAppender">
        <file>logs/application.log</file>
    </appender>
</configuration>