When you are calling a method of a webservice and want to omit an unrequired numeric variable that has a default value set coldfusion will throw the following error:
The fault returned when invoking the web service operation is:<br>
<pre>'' java.lang.IllegalArgumentException</pre>
Example:
<cfinvoke
webservice = "http://*.cfc?WSDL"
method="getFriendlyDay"
returnvariable="response"
refreshWSDL="true"
>
<cfinvokeargument name="dayNumber" omit="true"/>
</cfinvoke>
webservice component:
<cffunction name="getFriendlyDay" access="remote" returntype="any" output="no" description="get a friendly date from a number">
<cfargument name="dayNumber" type="numeric" required="no" default="0">
...
</cffunction>