Develop Reference

Which slf4j .jar dependency do I need?

I'm getting the following error:
Exception in thread "main" java.lang.NoClassDefFoundError:
org/slf4j/LoggerFactory
I need to include slf4j as a dependency but I'm not sure which jar file to download from https://repo1.maven.org/maven2/org/slf4j/.
I tried org/slf4j/slf4j-api which doesn't work. How do I determine which one is correct?

slf4j is a library that is used as an abstraction of each logging implementation framework such as log4j, logback or Jakarta Commons Logging. If your intent is to use it, you have to also define the concrete framework you want to use under the wood, for example for log4j, your pom dependencies will look like this:
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.30</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
Depending on the framework you want to use, the dependencies will be a bit different.
This excellent link will give your more details.

SLF4J is a logging API. Combine it with Logback (written by the same people as SLF4J) which implements that logging API:
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<scope>runtime</scope>
</dependency>
Find the latest stable versions on mvnrepository.com. Currently logback 1.2.11 and slf4J 1.7.32. Note the the vulnerabilities mentioned on logback 1.2.11 are because of an optional dependency on log4J 1.x (which you don't get automatically, so it's safe to use logback 1.2.11 at the time of writing).

Log4j2/slf4j - Should commons-logging.jar be removed from classpath?

My logging dependencies currently look like this:
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-bom</artifactId>
<version>2.9.1</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependencies>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.25</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
</dependency>
I noticed that commons-logging.jar is still in my classpath, for some reason. Should I exclude that or doesn't that cause any issues?
I didn't notice any problems so far, but I'm still wondering if that jar would still cause problems somehow.

There are dependencies that use commons-logging. If it's not present, you'll get NoClassDefFoundErrors when they attempt to log. If there were a possibility to have those not even try to use the dependency, it wouldn't be a problem. However that's not very likely.
However, if they use commons-logging but you're using SLF4J, then there's a problem. They're logging in the wrong place (from your point of view). This is where logging bridges come to work. They implement the public API of different logging frameworks, but redirect the logging to what you're using.
For SLF4J there are several bridges (both ways), so instead of bringing in commons-logging, you bring in jcl-over-slf4j. Libraries will think they're using commons-logging, when they're actually using SLF4J (which then uses an actual logging implementation like Logback).
Easy, huh? ;)

Yes, exclude the commons-logging dependency and add the log4j-jcl bridge instead:
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-jcl</artifactId>
</dependency>
SLF4J API is also redundant because it is already a transitive dependency of the log4j-slf4j-impl binding.

SLF4J + version 1.7.x by your slf4j binding is not compatible 1.6 [duplicate]

I realised that one of my projects uses slf4j 1.5.8 and Hibernate uses slf4j 1.6. While building with Maven it downloads both jars but I guess the class files of 1.5.8 are used. So, when I run the program i get following error:
SLF4J: The requested version 1.5.8 by your slf4j binding is not compatible with [1.6]
In pom.xml I have put
<dependencyManagement>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.6.1</version>
</dependency>
</dependencyManagement>
The 1.5.8 is part of dependency so it's downloaded on its own.

As you discovered yourself, there are two libraries (Hibernate and some other) transitively importing SLF4J in two different versions. Unfortunately the older version is being picked up by maven (there are some rules which dependency should be chosen by maven in this situation). The solution is to add the exclusion in the dependency that imports older version of SLF4J (com.example:foo-bar is example here):
<dependency>
<groupId>com.example</groupId>
<artifactId>foo-bar</artifactId>
<version>1.2.3</version>
<exclusions>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
</exclusion>
</exclusions>
</dependency>
If you still experience this problem, issue:
$ mvn dependency:tree
Look for 1.5.8 version and exclude it from all libraries importing it.

Excluding is quite unnecessary and maybe quite misleading. Instead, explicitly include the slf4j-api with the desired version in your projects pom file. That's it!
This approach takes advantage of Maven's transitivity rules: the nearest dependency declaration wins.

you can exclude the wrong version with something like this:
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate</artifactId>
<version>3.2.7.ga</version>
<exclusions>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
</exclusion>
</exclusions>
</dependency>

"log4j:WARN No appenders could be found" errors when running application from executable jar but no errors when running it inside IntelliJ

I am using log4j2 but some of my dependencies use log4j. When I run the application from an executable jar file I get only a couple log lines and the following message:
log4j:WARN No appenders could be found for logger (org.reflections.Reflections).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
But when I run the application inside IntelliJ it works as expected, no warnings and all logs produced.
I have used maven enforcer to ban log4j. I also tried adding the dependency but setting the scope to "provided".
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>[0.0,1.2.17)</version>
<scope>provided</scope>
</dependency>
I also did the above with a single version number instead of a range. All of these work for when it is run in IntelliJ but none of them work when the application is run as an executable jar.
The answers to the question How do you configure logging in Hibernate 4 to use SLF4J would suggest that I am getting this error message because log4j is somehow creeping into my jar and I can't seem to keep it out.
Any advice on how to fix this would be appreciated. Thanks.
Please note that I am using log4j2 and the following dependencies
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.25</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.8.2</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.2</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>2.8.2</version>
<type>pom</type>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-1.2-api</artifactId>
<version>2.8.2</version>
</dependency>

I used the following Maven command to find the dependency that was pulling in log4j.
mvn dependency:tree -Dincludes=log4j:log4j
It turns out that log4j was being pulled in by a Maven plugin (maven-hyperjaxb3-plugin) and for some reason maven-enforcer-plugin was not blocking it. The plugin wasn't triggered when I ran the application in IntelliJ so the dependency was not included in the classpath, but when compiled into an executable jar it was still being pulled in.
This FAQ http://logging.apache.org/log4j/2.x/faq.html#which_jars and the answer to this question Configuring log4j2 and log4j using a single log4j2 xml file were very helpful.
Just so it's clear, the issue was that log4j was making it into the jar and log4j must NOT be included in the classpath if your intention is to use log4j2.

"Failed to load class "org.slf4j.impl.StaticLoggerBinder"." [duplicate]

My application is to be deployed on both tcServer and WebSphere 6.1. This application uses ehCache and so requires slf4j as a dependency.
As a result I've added the slf4j-api.jar (1.6) jar to my war file bundle.
The application works fine in tcServer except for the following error:
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.
However, when I deploy in WebSphere I get a java.lang.NoClassDefFoundError: org.slf4j.impl.StaticLoggerBinder.
Also accompanied by Failed to load class "org.slf4j.impl.StaticMDCBinder"
I've checked the classpaths of both application servers and there is no other slf4j jar.
Does anyone have any ideas what may be happening here?

I had the same issue with WebSphere 6.1. As Ceki pointed out, there were tons of jars that WebSphere was using and one of them was pointing to an older version of slf4j.
The No-Op fallback happens only with slf4j -1.6+ so anything older than that will throw an exception and halts your deployment.
There is a documentation in SLf4J site which resolves this. I followed that and added slf4j-simple-1.6.1.jar to my application along with slf4j-api-1.6.1.jar which I already had.
If you use Maven, add the following dependencies, with ${slf4j.version} being the latest version of slf4j
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${slf4j.version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>${slf4j.version}</version>
</dependency>
This solved my issue.

This is for those who came here from google search.
If you use maven just add the following
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.5</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.5</version>
</dependency>
Or
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.5</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.6.4</version>
</dependency>

Simply add this to your pom.xml:
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.7.21</version>
</dependency>

Quite a few answers here recommend adding the slf4j-simple dependency to your maven pom file. You might want to check for the most current version.
At https://mvnrepository.com/artifact/org.slf4j/slf4j-simple
you'll find the latest version of the SLF4J Simple Binding. Pick the one that suites you best (still 1.7.32 from 2021-07 is the stable version as of 2021-10) and include it to your pom.xml.
For your convenience some dependencies are shown here - but they might not be up-to-date when you read this!
Alpha Version of 2021-08
<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-simple -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>2.0.0-alpha5</version>
</dependency>
Beta Version of Feb 2019
<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-simple -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.8.0-beta4</version>
</dependency>
Stable Version 2021-07
<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-simple -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.7.32</version>
</dependency>
I removed the scope test part thanks to the comment below.

You need to add following jar file in your classpath: slf4j-simple-1.6.2.jar. If you don't have it, please download it. Please refer to http://www.slf4j.org/codes.html#multiple_bindings

Sometime we should see the note from the warnin SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details..
This happens when no appropriate SLF4J binding could be found on the class path
You can search the reason why this warning comes.
Adding one of the jar from *slf4j-nop.jar, slf4j-simple.jar, slf4j-log4j12.jar, slf4j-jdk14.jar or logback-classic.jar* to the class path should solve the problem.
compile "org.slf4j:slf4j-simple:1.6.1"
for example add the above code to your build.gradle or the corresponding code to pom.xml for maven project.

I was facing same error. I have configured slf4j-api, slf4j-log4j12 and log4j, in my local development. All configuration was fine, but slf4j-log4j12 dependency which I copied from mvnrepository had test scope <scope>test</scope>. When I removed this every thing is fine.
Some times silly mistakes breaks our head ;)

put file slf4j-log4j12-1.6.4.jar in the classpath will do the trick.

SLF4j is an abstraction for various logging frameworks. Hence apart from having slf4j you need to include any of your logging framework like log4j or logback (etc) in your classpath.
To have an idea refer the First Baby Step in http://logback.qos.ch/manual/introduction.html

If you are using maven to dependency management so you can just add following dependency in pom.xml
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.5.6</version>
</dependency>
For non-Maven users
Just download the library and put it into your project classpath.
Here you can see details: http://www.mkyong.com/wicket/java-lang-classnotfoundexception-org-slf4j-impl-staticloggerbinder/

I got into this issue when I get the following error:
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.
when I was using slf4j-api-1.7.5.jar in my libs.
Inspite I tried with the whole suggested complement jars, like slf4j-log4j12-1.7.5.jar, slf4j-simple-1.7.5 the error message still persisted. The problem finally was solved when I added slf4j-jdk14-1.7.5.jar to the java libs.
Get the whole slf4j package at http://www.slf4j.org/download.html

<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.7.21</version>
</dependency>
Put above mentioned dependency in pom.xml file

I was facing the similar problem with Spring-boot-2 applications with Java 9 library.
Adding the following dependency in my pom.xml solved the issue for me:
<dependency>
<groupId>com.googlecode.slf4j-maven-plugin-log</groupId>
<artifactId>slf4j-maven-plugin-log</artifactId>
<version>1.0.0</version>
</dependency>

Slf4j is a facade for the underlying logging frameworks like log4j, logback, java.util.logging.
To connect with underlying frameworks, slf4j uses a binding.
log4j - slf4j-log4j12-1.7.21.jar
java.util.logging - slf4j-jdk14-1.7.21.jar etc
The above error is thrown if the binding jar is missed. You can download this jar and add it to classpath.
For maven dependency,
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.21</version>
</dependency>
This dependency in addition to slf4j-log4j12-1.7.21.jar,it will pull slf4j-api-1.7.21.jar as well as log4j-1.2.17.jar into your project
Reference: http://www.slf4j.org/manual.html

Please add the following dependencies to pom to resolve this issue.
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.7.25</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.25</version>
</dependency>

As an alternative to the jar inclusion and pure maven solutions, you can include it from maven with gradle.
Example for version 1.7.25
// https://mvnrepository.com/artifact/org.slf4j/slf4j-simple
api group: 'org.slf4j', name: 'slf4j-simple', version: '1.7.25'
Put this within the dependencies of your build.gradle file.

In the Websphere case, you have an older version of slf4j-api.jar, 1.4.x. or 1.5.x lying around somewhere. The behavior you observe on tcServer, that is fail-over to NOP, occurs on slf4j versions 1.6.0 and later. Make sure that you are using slf4j-api-1.6.x.jar on all platforms and that no older version of slf4j-api is placed on the class path.

I am working in a project Struts2+Spring. So it need a dependency slf4j-api-1.7.5.jar.
If I run the project, I am getting error like
Failed to load class "org.slf4j.impl.StaticLoggerBinder"
I solved my problem by adding the slf4j-log4j12-1.7.5.jar.
So add this jar in your project to solve the issue.

As SLF4J Manual states
The Simple Logging Facade for Java (SLF4J) serves as a simple facade
or abstraction for various logging frameworks, such as
java.util.logging, logback and log4j.
and
The warning will disappear as soon as you add a binding to your class path.
So you should choose which binding do you want to use.
NoOp binding (slf4j-nop)
Binding for NOP, silently discarding all logging.
Check fresh version at https://search.maven.org/search?q=g:org.slf4j%20AND%20a:slf4j-nop&core=gav
Simple binding (slf4j-simple)
outputs all events to System.err. Only messages of level INFO and higher are printed. This binding may be useful in the context of small applications.
Check fresh version at https://search.maven.org/search?q=g:org.slf4j%20AND%20a:slf4j-simple&core=gav
Bindings for the logging frameworks (java.util.logging, logback, log4j)
You need one of these bindings if you are going to write log to a file.
See description and instructions at https://www.slf4j.org/manual.html#projectDep
My opinion
I would recommend Logback because it's a successor to the log4j project.
Check latest version of the binding for it at https://search.maven.org/search?q=g:ch.qos.logback%20AND%20a:logback-classic&core=gav
You get console output out of the box but if you need to write logs into file just put FileAppender configuration to the src/main/resources/logback.xml or to the src/test/resources/logback-test.xml just like this:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<!-- encoders are assigned the type
ch.qos.logback.classic.encoder.PatternLayoutEncoder by default -->
<encoder>
<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
</encoder>
</appender>
<appender name="FILE" class="ch.qos.logback.core.FileAppender">
<file>logs/logs.log</file>
<encoder>
<pattern>%date %level [%thread] %logger{10} - %msg%n</pattern>
</encoder>
</appender>
<root level="debug">
<appender-ref ref="STDOUT" />
<appender-ref ref="FILE" />
</root>
<logger level="DEBUG" name="com.myapp"/>
</configuration>
(See detailed description in manual: https://logback.qos.ch/manual/configuration.html)

this can resolve using the same version. I tried this and solved it
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.5</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.5</version>
</dependency>

I added this dependency to resolve this issue:
https://mvnrepository.com/artifact/org.slf4j/slf4j-simple/1.7.25

Most likely your problem was because of <scope>test</scope> (in some cases also <scope>provided</scope>), as mentioned #thangaraj.
Documentation says:
This scope indicates that the dependency is not required for normal
use of the application, and is only available for the test compilation
and execution phases. Test dependencies aren’t transitive and are only present for test and execution classpaths.
So, if you don't need dependecies for test purposes then you can use instead of (what you will see in mvnrepository):
<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-nop -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-nop</artifactId>
<version>1.7.24</version>
<scope>test</scope>
</dependency>
Without any scopes (by default would be compile scope when no other scope is provided):
<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-nop -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-nop</artifactId>
<version>1.7.25</version>
</dependency>
This is the same as:
<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-nop -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-nop</artifactId>
<version>1.7.25</version>
<scope>compile</scope>
</dependency>

Here are my 5 cents...
I had the same issues while running tests. So I've fixed it by adding an implementation for the test runtime only. I'm using gradle for this project.
// https://mvnrepository.com/artifact/ch.qos.logback/logback-classic
testRuntimeOnly group: 'ch.qos.logback', name: 'logback-classic',
version: '1.2.3'

encountered the same problem on payara 5.191
jcl-over-slf4j together with slf4j-log4j12 solved the problem
<properties>
<slf4j.version>1.7.29</slf4j.version>
</properties>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${slf4j.version}</version>
<type>jar</type>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>jcl-over-slf4j</artifactId>
<version>${slf4j.version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>${slf4j.version}</version>
</dependency>

As per the SLF4J Error Codes
Failed to load class org.slf4j.impl.StaticLoggerBinder
This warning message is reported when the org.slf4j.impl.StaticLoggerBinder class could not be loaded into memory. This happens when no appropriate SLF4J binding could be found on the class path. Placing one (and only one) of slf4j-nop.jar slf4j-simple.jar, slf4j-log4j12.jar, slf4j-jdk14.jar or logback-classic.jar on the class path should solve the problem.
Note that slf4j-api versions 2.0.x and later use the ServiceLoader mechanism. Backends such as logback 1.3 and later which target slf4j-api 2.x, do not ship with org.slf4j.impl.StaticLoggerBinder. If you place a logging backend which targets slf4j-api 2.0.x, you need slf4j-api-2.x.jar on the classpath. See also relevant faq entry.
SINCE 1.6.0 As of SLF4J version 1.6, in the absence of a binding, SLF4J will default to a no-operation (NOP) logger implementation.
If you are responsible for packaging an application and do not care about logging, then placing slf4j-nop.jar on the class path of your application will get rid of this warning message. Note that embedded components such as libraries or frameworks should not declare a dependency on any SLF4J binding but only depend on slf4j-api. When a library declares a compile-time dependency on a SLF4J binding, it imposes that binding on the end-user, thus negating SLF4J's purpose.

for me the total fix was:
1
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.5</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.5</version>
</dependency>
plus
2 create file log4j.properties
and add inside:
# Root logger option
log4j.rootLogger=INFO, stdout
# Direct log messages to stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
else I got some exceptions in the console.

According to SLF4J official documentation
Failed to load class org.slf4j.impl.StaticLoggerBinder
This warning message is reported when the
org.slf4j.impl.StaticLoggerBinder class could not be loaded into
memory. This happens when no appropriate SLF4J binding could be found
on the class path. Placing one (and only one) of slf4j-nop.jar,
slf4j-simple.jar, slf4j-log4j12.jar, slf4j-jdk14.jar or
logback-classic.jar on the class path should solve the problem.
Simply add this jar along with slf4j api.jar to your classpath to get things done.
Best of luck

I solve it adding this library: slf4j-simple-1.7.25.jar
You can download this in official web https://www.slf4j.org/download.html

For me the issue was:
Using Hibernate, I saw that it already used slf4j, and it was in my classpath already, so I decided to use it.
The next step - adding imlementor for slf4j, so I added to maven:
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-jdk14</artifactId>
<version>1.7.25</version>
</dependency>
But it failed with error! SLF4J: Failed to load class “org.slf4j.impl.StaticLoggerBinder”
The solution was:
Hibernate's dependency of slf4j was version 1.7.26, and I added minor version dependency 1.7.25. So when I fixed this - all became OK

I know this post is a little old, but in case anyone else runs into this problem:
Add slf4j-jdk14-X.X.X.jar to your CLASSPATH (where X.X.X is the version number - e.g. slf4j-jdk14-1.7.5.jar).
HTH
Peter