Mahout 0.8

exception

javax.servlet.ServletException: java.lang.NoClassDefFoundError: Could not initialize class org.apache.mahout.cf.taste.impl.model.file.FileDataModel
	com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:424)
	com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:497)
	com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:684)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
root cause

java.lang.NoClassDefFoundError: Could not initialize class org.apache.mahout.cf.taste.impl.model.file.FileDataModel
	RecommenderIntro.<init>(RecommenderIntro.java:25)