SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder"

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

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>

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>

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>

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>

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

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'

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

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.

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

I use Jena and I add the fellowing dependence to pom.xml

<dependency> 
  <groupId>ch.qos.logback</groupId>
  <artifactId>logback-classic</artifactId>
  <version>1.0.13</version>
</dependency>

I try to add slf4j-simple but it just disappear the "SLF4J: Failed to load class “org.slf4j.impl.StaticLoggerBinder”" error but logback-classic show more detail infomation.

The official document

the solution is indicated on their official website :

> 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. 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.

solution : I have added to my project using maven research on intellij and i have chosen the slf4j-jdk14.jar.

I did not add any dependencies, I just change the way I was consuming them.

Preview code

(Uncomment this code if you are using elastic search version < 7.0)

IndexRequest indexRequest = new IndexRequest(
  "twitter",
  "tweets",
  id // this is to make our consumer idempotent
).source(record.value(), XContentType.JSON);

Current code

IndexRequest indexRequest = new IndexRequest("tweets")
  .source(record.value(), XContentType.JSON)
  .id(id); // this is to make our consumer idempotent

I am using bulkrequest and with that I remove that error.

you can simply add the dependency by using the below

<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>