Read parameters names using Eclipse Luna

I am trying to implement some simple custom tags parsing xmls and then using reflection to match up attributes with constructor parameters by name, i went trought some tutorial and found out that compliance to 1.8 and "store information on method parameters" check in the java compiler section should do the trick. but on

System.out.println(params[i].getName());

i keep getting

arg0 arg1 ecc...

instead of the expected

x y ecc...