Problem

If you are using a Bamboo variable to populate a script or function that expects a numerical value, but the Bamboo variable is not correctly referenced, the following will appear in the job log

 Can't assign value '${variable}' to attribute <name>, reason: class java.lang.NumberFormatException with message 'For input string: "${variable}"

Cause

Bamboo variables need to have bamboo prepended to the variable name when passed to Tasks, for example

variable = ${bamboo.variable_name}

instead of 

variable = ${variable_name}

If the identifier bamboo is not added, Bamboo will read this as a string, and not substitute the variable.

Resolution

Please ensure that the variable is correctly passed as ${bamboo.variable_name}.