Pretty much title. I need to differentiate between something scary and something safe without having to look inside the function body. What is the standard in Java? I can't put "!" in function names.
Example:
// convenient when you don't want to update the reference in the objects that were using
// param
BiFunction<T,U,T> mutableTransformation = (param,operand) -> {
//... do operations that alter param using operand
return param;
}