Thread: Eclipse List Type Safety Warning

I have a warning in Eclipse showing up, and I'm not sure why.
The warning reads:

Type safety: The expression of type List needs unchecked conversion to conform to List<String>

I think I understand what the warning is saying, but I do not understand why it is saying it.

The code in question is here:

List<String> airports = AirportQuery.getAllAirports("startup");

Here is the method declaration for AirportQuery.getAllAirports(String)

public static List<String> getAllAirports(String user) {
...
}

Now, I don't understand why it feels it needs any conversion to conform to anything. The method clearly returns the exact same type of list I am setting to, so I don't see the problem.
Is this just a bug in Eclipse or something?

What do you mean? It's just a list of Strings (representing the 3 digit IATA code for a list of airports).

I'm currently assuming this is a bug, because when I suppressed the warning, Eclipse then started complaining that there is nothing to suppress...

I know warnings can be ignored. But this particular warning could not be annotated as ignore or suppress without the IDE creating a second warning, telling me that the ignore or suppress annotation was unnecessary.
I don't see why this code will change anything, but here you go regardless (maybe there is something I don't know about and you do):

public static List<String> getAllAirports(String user) {
		List<String> ret = new ArrayList<String>();
		String exactURL = QUERY_LOCATION+USERNAME+user;
		try {
			URL url = new URL(exactURL);
			logger.info("Querying: "+url.getPath());
			Document document = XMLUtilities.loadXMLFromURL(url);
			Element element = XMLUtilities.getChildElement(document, "airports");
			NodeList list = element.getElementsByTagName("airport");
			for(int i=0;i<list.getLength();i++) {
				String code = XMLUtilities.getValueOfNode(list.item(i),"code");
				ret.add(code);
			}
		} catch(Exception ex) {
			logger.throwing("AirportQuery", "getAllAirports", ex);
			logger.info("Exact URL: "+exactURL);
		}
		return ret;
	}

Regardless, after fiddling around with my project's build path (there was some issues with it), the warning went away...

In case anyone else comes across this issue, my project was a Maven Project. Eclipse was claiming the JRE being used was 1.7, but Maven apparently defaults to 1.5. After specifying the source and target version for maven's compiler plugin in the project's pom as 1.7, I removed the JRE from the project's Eclipse Properties, performed a Maven Update, and did a full maven clean and maven install. And poof, the warnings went away...