Dependency to slf4j-simple should be removed

[simasch]

Because of

<!-- Added to provide logging output as Vaadin uses -->
<!-- the unbound SLF4J no-operation (NOP) logger implementation -->
<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-simple</artifactId>
</dependency>

the application fails to start because there are multiple

SLF4J: Class path contains multiple SLF4J providers.
SLF4J: Found provider [org.slf4j.simple.SimpleServiceProvider@3569fc08]
SLF4J: Found provider [ch.qos.logback.classic.spi.LogbackServiceProvider@20b12f8a]
SLF4J: See https://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual provider is of type [org.slf4j.simple.SimpleServiceProvider@3569fc08]
[main] INFO org.springframework.boot.devtools.restart.RestartApplicationListener - Restart disabled due to an agent-based reloader being active
Exception in thread "main" java.lang.IllegalArgumentException: LoggerFactory is not a Logback LoggerContext but Logback is on the classpath. Either remove Logback or the competing implementation (class org.slf4j.simple.SimpleLoggerFactory loaded from file:/C:/Users/simon/.m2/repository/org/slf4j/slf4j-simple/2.0.7/slf4j-simple-2.0.7.jar). If you are using WebLogic you will need to add 'org.slf4j' to prefer-application-packages in WEB-INF/weblogic.xml: org.slf4j.simple.SimpleLoggerFactory
at org.springframework.util.Assert.instanceCheckFailed(Assert.java:713)
at org.springframework.util.Assert.isInstanceOf(Assert.java:632)
at org.springframework.boot.logging.logback.LogbackLoggingSystem.getLoggerContext(LogbackLoggingSystem.java:381)
at org.springframework.boot.logging.logback.LogbackLoggingSystem.beforeInitialize(LogbackLoggingSystem.java:122)
at org.springframework.boot.context.logging.LoggingApplicationListener.onApplicationStartingEvent(LoggingApplicationListener.java:238)
at org.springframework.boot.context.logging.LoggingApplicationListener.onApplicationEvent(LoggingApplicationListener.java:220)
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.multicastInitialEvent(EventPublishingRunListener.java:136)
at org.springframework.boot.context.event.EventPublishingRunListener.starting(EventPublishingRunListener.java:75)
at org.springframework.boot.SpringApplicationRunListeners.lambda$starting$0(SpringApplicationRunListeners.java:54)
at java.base/java.lang.Iterable.forEach(Iterable.java:75)
at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:118)
at org.springframework.boot.SpringApplicationRunListeners.starting(SpringApplicationRunListeners.java:54)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:302)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1304)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1293)

[RatzzFatzz]

@simasch I came across the same problem. I excluded the package in my pom:

        <dependency>
            <groupId>org.vaadin.addons.componentfactory</groupId>
            <artifactId>vaadin-css-grid-layout</artifactId>
            <version>3.0.0</version>
            <exclusions>
                <exclusion> 
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-simple</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

This is just a workaround.