This problem also occurs with other methods but I am just using ArrayList.contains(Object o) as an example.
The method appears twice in Eclipse's method suggestions but one of them with a percentage. As far as I can tell it seems to be a percentage unique to that method.
The methods do the same thing as they both have the same name and parameters so I have no clue why this was happening.
I also though maybe it was some kind of progress counter for the completion of the method, but this makes no sense if there is one without the percentage there too.