Setting a default value to a number field using Scriptrunner Behaviours - language problem

[Daniel Pollak]

We followed the suggested procedure of setting a default value and this works fine for the English setting of Jira. 

def desc = getFieldById("customfield_12894")
        if (! desc.getValue()) {
            desc.setFormValue("""0""")
        }

The problem we are trying to solve arises if we set Jira to German or Czech when entering decimal values:

If the user enters it with a dot for a comma Jira complains "This is not a number":

If you enter it with a comma (according to czech or german language settings) this would work, only behaviours does not recognize this as a valid value and the  desc.getValue() delivers a false:

and Behaviours sets the default value 0, ignoring the decimal value:

So the user experiences this as Jira taking away the comma value without them really konwing why.

Can anyone advise an alternative to this? We tried several alterations but without success. 

Thank you in advance, BR, Daniel.