Failed to load class "org.slf4j.impl.StaticLoggerBinder", Spring Boot - spring

Question

I'm using Spring Boot 1.5.8. SLF4J doesn't seem to be working for me. Here is what I get in the console at the beginning of a project run. The below error shows appears :
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
START : EDIT 1 :
My console doesn't log the below:
LOGGER.error("ERROR");
LOGGER.error("WARN");
LOGGER.error("INFO");
LOGGER.error("DEBUG");
LOGGER.error("TRACE");
All I get is those three lines of error(warning) as the first lines in my console.
END : EDIT 1 :
I looked up the internet and found multiple issues titled as this,tried the suggestions but that didn't resolve my issue. I came across this stackoverflow question where Konstantinos hints at the possibility of presence of multiple slf4j dependencies. Other solutions on the internet also suggested that; even the official site confirmed that to be the reason for such error.
Also checked my effective pom just to eliminate this possibility and found that my effective pom does contain all the 4 dependencies that he mentioned. The general suggestion is that the pom should contain only one of these four dependencies. But , since this was all handled by Spring boot, I'm a bit confused as to how do I go about resolving this, because I never exclusively included any slf4j dependency in my pom. So I'm unable to follow the suggestion.
pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.codingethics.flightreservation</groupId>
<artifactId>flightreservation</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>flightreservation</name>
<description>Flight Reservation Application</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.8.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.tomcat.embed/tomcat-embed-jasper -->
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
<scope>provided</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.servlet/jstl -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/com.itextpdf/itextpdf -->
<dependency>
<groupId>com.itextpdf</groupId>
<artifactId>itextpdf</artifactId>
<version>5.5.13</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-mail -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-mail</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
application.properties :
spring.datasource.url=jdbc:mysql://localhost:3306/reservation
spring.datasource.username=root
spring.datasource.password=password
spring.jpa.show-sql=true
spring.mvc.view.prefix=/WEB-INF/jsps/
spring.mvc.view.suffix=.jsp
server.context-path=/flightreservation
spring.mail.host=smtp.gmail.com
spring.mail.port=587
spring.mail.username=<myusername>
spring.mail.password=<mypwd>
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true
spring.mail.properties.mail.smtp.starttls.required=true
Why does this dependency-conflict(if at all that's the case here) happen in a Spring Boot project. Isn't Spring Boot meant to be looking after these beforehand.
Any sort of help/ guidance is highly appreciated.
START : EDIT for #Antot
I get NoClassDefFoundError.(followed steps as advised by you) :
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory
at org.springframework.boot.SpringApplication.<clinit>(SpringApplication.java:179)
at com.codingethics.flightreservation.FlightreservationApplication.main(FlightreservationApplication.java:10)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.logging.LogFactory
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 2 more
END : EDIT for #Antot

Answer 1

You might first want to check if something that isn't managed by Spring Boot is pulling in additional dependencies. You can do this with mvn dependency:tree to see what is pulling in what.
If that doesn't give a hint in the right direction it might be that one of your downloaded dependencies got borked. You might want to purge the local repository. You can do this with mvn dependency:purge-local-repository to remove all your dependencies from your local maven repository.
Then when doing mvn package (or another task that will compile and build the jar) will (re)download the jars and hopefully in a correct way without corruption.