Logback

Logback-classic module requires the presence of slf4j-api.jar and logback-core.jar in addition to logback-classic.jar on the classpath.
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.5</version>
</dependency>

<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.0.13</version>
</dependency>
logback is divided into three modules, logback-core, logback-classic and logback-access.
To ensure that all loggers can eventually inherit a level, the root logger always has an assigned level. By default, this level is DEBUG.
the initialization steps that logback follows to try to configure itself:
Logback tries to find a file called logback.groovy in the classpath.
If no such file is found, logback tries to find a file called logback-test.xml in the classpath.
If no such file is found, it checks for the file logback.xml in the classpath..
If neither file is found, logback configures itself automatically using the BasicConfigurator which will cause logging output to be
directed to the console.