NoClassDefFoundError: org/slf4j/impl/StaticLoggerBinder (with SLF4J, Logback and Spring Boot)

Since of nowhere I getting the error message that the class StaticLoggerBinder was not found. I guess it have something to do with the Spring-Boot API. Any solutions to the problem?

pom.xml:

      <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
                <version>2.5.5</version>
            </dependency>
        <!-- json request -->
        <dependency>
            <groupId>org.json</groupId>
            <artifactId>json</artifactId>
            <version>20210307</version>
        </dependency>

        <!-- Log -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>2.0.7</version>
        </dependency>
        <!-- logger -->
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.4.8</version>
        </dependency>

logback.xml:

<configuration>

    <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <file>logs/reportsystem.log</file>
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <fileNamePattern>logs/reportsystem.%d{yyyy-MM-dd}.log</fileNamePattern>
        </rollingPolicy>
        <encoder>
            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>

    <appender name="CUSTOM" class="de.netzmelden.reportsystem.logging.CustomConsoleAppender">
    
        <encoder>
            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{1} - %msg%n</pattern>
        </encoder>
    </appender>


    <root level="info">
        <appender-ref ref="FILE"/>
        <appender-ref ref="CUSTOM"/>
    </root>

</configuration>

exception:

Exception in thread "main" java.lang.NoClassDefFoundError: org/slf4j/impl/StaticLoggerBinder
    at org.springframework.boot.logging.logback.LogbackLoggingSystem.getLoggerContext(LogbackLoggingSystem.java:293)
    at org.springframework.boot.logging.logback.LogbackLoggingSystem.beforeInitialize(LogbackLoggingSystem.java:118)
    at org.springframework.boot.context.logging.LoggingApplicationListener.onApplicationStartingEvent(LoggingApplicationListener.java:232)
    at org.springframework.boot.context.logging.LoggingApplicationListener.onApplicationEvent(LoggingApplicationListener.java:213)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:176)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:169)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:143)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:131)
    at org.springframework.boot.context.event.EventPublishingRunListener.starting(EventPublishingRunListener.java:76)
    at org.springframework.boot.SpringApplicationRunListeners.lambda$starting$0(SpringApplicationRunListeners.java:53)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
    at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:117)
    at org.springframework.boot.SpringApplicationRunListeners.starting(SpringApplicationRunListeners.java:53)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:329)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1343)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1332)
    at de.netzmelden.reportsystem.ReportSystem.main(ReportSystem.java:72)
Caused by: java.lang.ClassNotFoundException: org.slf4j.impl.StaticLoggerBinder
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
    ... 17 more

I've tried using older versions of slf4j-api and logback-classic, but with no success.

The question is why does my program need StaticLoggerBinder and throw an exception about it when I'm using the newest slf4j-api and logback-classic versions which shouldn't care about it?

Any suggestions on how to solve the problem would be appreciated!

Solution

Spring Boot 2.5.5 depends on logback 1.2.x and SLF4J 1.x.

SLF4J implementation significantly changed between 1.x and 2.x (and as a consequence logback 1.2.x vs. 1.3.x/1.4.x) so that some usages are not compatible anymore. Typically usage of StaticLoggerBinder is not possible anymore.

The 1st version of Spring Boot compatible with SLF4J 2.x and logback 1.3.x/1.4.x is the 3.0.0.

You need to either stay with logback 1.2.x and SLF4J 1.x, or also upgrade Spring Boot to 3.x. I would recommend the latter obviously.