Exception - java.lang.NoClassDefFoundError: org/apache/poi/ss/usermodel/Font

If the exception as -

org.springframework.web.util.NestedServletException: 

Handler processing failed; 

nested exception is java.lang.NoClassDefFoundError: 

org/apache/poi/ss/usermodel/Font 

shows, adding the poi jar from http://poi.apache.org/download.html 

helps to get going.