LinkageError when using plugins

[brianhks]

An example of this error is shown below when using the Kairos plugin while reporting JMX metrics from Cassandra:
Caused by: java.lang.LinkageError: loader constraint violation: when resolving method "org.slf4j.impl.StaticLoggerBinder.getLoggerFactory()Lorg/slf4j/ILoggerFactory;" the class loader (instance of org/kairosdb/metrics4j/configuration/PluginClassLoader) of the current class, org/slf4j/LoggerFactory, and the class loader (instance of sun/misc/Launcher$AppClassLoader) for the method's defining class, org/slf4j/impl/StaticLoggerBinder, have different Class objects for the type org/slf4j/ILoggerFactory used in the signature

[brianhks]

When using a plugin that includes slf4j and the parent application also uses slf4j but a different version this error can occur. The solution is to remove the slf4j jar from the plugin folder and let the plugin load the parent dependency.