Java doesn't. (It's just convention)
Delphi does. I believe C# does.
What other languages do?
Edit: I should have given an example:
Delphi: (beware, it's been a while, I may get this wrong)
type
TSomething = class
fEmployeeNum: String;
property employeeNum: String read fEmployeeNum write setEmployeeNum;
end;
procedure TSomething.setEmployeeNum(var val: String);
begin
fEmployeeNum := val;
end;