Root exception is java.lang.ClassNotFoundException?: org.apache.commons.dbcp.BasicDataSourceFactory?:

according to this : ​http://mail-archives.apache.org/mod_mbox/tomcat-users/200903.mbox/%3Ca2d59f0d0903031254h78e097b5u66cb2639f82166dd@mail.gmail.com%3E

there is a problem in context.xml :

<Context path="/molgenis" docBase="molgenis4mpd" debug="5" reloadable="true" crossContext="true">		
	<Resource 
		name="jdbc/molgenisdb" 
		auth="Container" 
		factory="org.apache.commons.dbcp.BasicDataSourceFactory" 
		type="javax.sql.DataSource"