java.lang.NoClassDefFoundError: org/dom4j/Namespace at org.apache.poi.openxml4j.opc.internal.unmarshallers.PackagePropertiesUnmarshaller

BUG:
While i was trying to read uploaded excel by apache poi i got following error:
java.lang.NoClassDefFoundError: org/dom4j/Namespace

at org.apache.poi.openxml4j.opc.internal.unmarshallers.PackagePropertiesUnmarshaller.<clinit>(PackagePropertiesUnmarshaller.java:49)

FIX:
I downloaded dom4j.jar and add it to classpath.
You can download the jar from here.