Difference between $value and $!value

Question

Hey there,

I looked on several edit.vm and view.vm to understand how everything works. But there is one different I do not understand: What is the difference between $value and $!value?

To me something like "#if (!$value)" would make sense. But a view.vm with only "$!value" instead of "$value" ? I don t get it!

Thanks in advance :) !

Igor Sereda [ALM Works] · Accepted Answer

Without "!" $value would generate velocity warning if value is null, and the substituted value will be in fact "$value", not replaced with en empty string.

See http://velocity.apache.org/engine/devel/user-guide.html#quietreferencenotation