Before we jump into the rest of the steps to develop an application, it is good practice to define a log level and format. It is, however, optional but good practice to print the logs in a desired format, along with various logging levels. For this, add an XML file called logback.xml with following content in it:

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <layout class="ch.qos.logback.classic.PatternLayout">
      <Pattern>
        %d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n
      </Pattern>
    </layout>
  </appender>
  <logger name="com.nilangpatel.worldgdp" level="debug" additivity="false">
    <appender-ref ref="STDOUT" />
  </logger>
  <root level="debug">
    <appender-ref ref="STDOUT" />
  </root>
</configuration>

Logback was developed as a successor to the popular Log4j project, and is used as a logging framework for Java applications. This configuration defines the pattern, along with the logging level. To enable logback in your application, you need to add following dependencies to pom.xml:

  <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-classic</artifactId>
      <version>${logback.version}</version>
  </dependency>
  <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-core</artifactId>
      <version>${logback.version}</version>
  </dependency>