slf4j and opensaml

Using opensaml pulls in a dependency for SL4J through it's usage of xmltooling. To resolve the dependcy issues just add the following to your pom.xml file:

    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.5.5</version>
    </dependency>

 This snippet pulls in the necessary jars to configure SLF4j to use log4j for it's logging backend. Of course you could any other supported SLF4j logging backend and version. Just replace slf4j-log4j12 with another backend jar name.