Method that will try to convert value of this node to a Java
double. Numbers are coerced using default Java rules; booleans convert to 0.0 (false) and 1.0 (true), and Strings are parsed using default Java language integer parsing rules.
If representation can not be converted to an int (including structured types like Objects and Arrays), default value of 0.0 will be returned; no exceptions are thrown.
@since 1.9 (replaces getValueAsDouble
)