NoClassDefFoundError: org/slf4j/impl/StaticLoggerBinder

Question

I'm trying to run the sample tiles example given here.

Below is my POM.xml:

<dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.tiles</groupId>
            <artifactId>tiles-api</artifactId>
            <version>2.1.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.tiles</groupId>
            <artifactId>tiles-core</artifactId>
            <version>2.1.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.tiles</groupId>
            <artifactId>tiles-jsp</artifactId>
            <version>2.1.2</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.5.2</version>
        </dependency>

When I'm trying to run the example the below error is thrown:

Sep 17, 2010 11:59:43 PM org.apache.catalina.core.StandardContext listenerStart
SEVERE: Error configuring application listener of class      org.apache.tiles.web.startup.TilesListener
java.lang.NoClassDefFoundError: org/slf4j/impl/StaticLoggerBinder
at org.slf4j.LoggerFactory.<clinit>(LoggerFactory.java:60)
at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:155)
at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:131)
at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:685)
at org.apache.tiles.web.startup.TilesListener.<init>(TilesListener.java:49)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)

Any idea?

I spent 30 minutes googling for this but could not find a possible sollution.

Please help me...

Answer 1

You have included a dependency on the SLF4J API, which is what you use in your application for logging, but you must also include an implementation that does the real logging work.

For example to log through Log4J you would add this dependency:

    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.5.2</version>
    </dependency>

The recommended implementation would be logback-classic, which is the successor of Log4j, made by the same guys that made SLF4J and Log4J:

<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-classic</artifactId>
    <version>0.9.24</version>
</dependency>

Note: The versions may be incorrect.