reading integer values from properties file

Hi

I am using Camel API "propertyPlaceholder" to access my properties. All the
String values are resolved without any issues. Can you please provide any
insight on reading integer values?

Camel Version = 2.4

*Configuration:*

<camelContext..>
<propertyPlaceholder id="properties"
location="file:/usr/config/properties/params.properties" />
...

<property name="retryLimit" value="{{maxRetries.DEV}}" />

*params.properties*
maxRetries.DEV = 10

*Exception:*

org.apache.camel.RuntimeCamelException: java.lang.NumberFormatException: For
input string: "{{maxRetries.DEV}}"

Please help.

Thanks
Bala