How do I obtain or create a Logger?

Since JDK 1.4 a logging API was introduced into the Java class libraries. This
API enable our application to logs some messages to record our application
activities.

To create an instance of Logger we can call the Logger.getLogger()
factory method which will return the available logger for the given namespace or
it will create a new one when it doesn’t exist.

package org.kodejava.example.util.logging;

import java.util.logging.Logger;

public class LoggingDemo {
    public static void main(String[] args) {
        //
        // Obtaining an instance of Logger. This will create a new Logger
        // is it doesn't exist.
        //
        Logger log = Logger.getLogger(LoggingDemo.class.getName());

        //
        // Log some message using a different type of severity leve.
        //
        log.info("Info Message");
        log.warning("Warning Message");
        log.severe("Severe Message");
        log.config("Config Message");
        log.fine("Fine Message");
        log.finer("Finer Message");
        log.finest("Finest Message");
    }
}

After we create the Logger instance we can create a message log
by calling the logging method such as info(String message),
warning(String message) and severe(String message).
Below are some message produces by the Logger.

27 Apr 09 13:01:07 org.kodejava.example.util.logging.LoggingDemo main
INFO: Info Message
27 Apr 09 13:01:07 org.kodejava.example.util.logging.LoggingDemo main
WARNING: Warning Message
27 Apr 09 13:01:07 org.kodejava.example.util.logging.LoggingDemo main
SEVERE: Severe Message

Wayan

Programmer, runner, recreational diver, live in the island of Bali, Indonesia. Mostly programming in Java, creating web based application with Spring Framework, Hibernate / JPA.

Leave a Reply