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"Unable to parse the if-then expression" with error "javax.xml.xpath.XPathExpressionException" with Cast Iron

Technote (troubleshooting)


Receiving the error message "Unable to parse the if-then expression" with error "javax.xml.xpath.XPathExpressionException"


The reason for this error message is that the variable will hold an empty string and when performing the if-condition, the XPATH will convert the empty string to double to perform the validation (if the condition is to check for numeric values) and this will cause the above error message.

Resolving the problem

To verify, check the maestro.out file which is located under /var/log folder. In this file, if you see the below statements, check the map output section of the activity where the mapping is done for the variable being used in the if-then condition.

SEVERE [com.approuter.maestro]: Unable to parse the if-then expression
; Line#: 1; Column#: -1
net.sf.saxon.trans.DynamicError: ValidationException: Cannot convert string "" to a double

Other possible reasons for this error message are in the Studio release notes under "XPath Expressions".

Historical Number


Product Alias/Synonym

Cast Iron Solution
Cast Iron Operating System
Cast Iron Studio

Document information

More support for: WebSphere Cast Iron Cloud integration
Appliance Runtime

Software version:,

Operating system(s): Linux, Windows

Reference #: 1453135

Modified date: 25 November 2010

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