Question about type inference.

[Denis DEBARBIEUX]

Hi all,

I'm trying to run examples with type inference.

The following example fails:

public class Main{
/
//public static void main(String[] args) {//
//	System.out.println("start");//
//	Set<List<String>> stream = getStream();		//
//	stream.stream().filter(set -> set.size() == 0).forEach(System.out::println);//
//	System.out.println("end");//
//}//
//
//private static Set<List<String>> getStream() {//
//	Set<List<String>> stream = new HashSet<>();//
//	add(stream, Collections.emptyList()); // fail//
//	// Main.<List<String>>add(stream, Collections.emptyList()); // OK		//
//	return Collections.unmodifiableSet(stream);//
//}//
//	//
//private static <T> void add(Set<T> set, T element) {//
//	set.add(element);//
//}//
//
}

//lambda-8-b69-windows-i586-17_dec_2012/jdk1.8.0/bin/javac test/Main.java//
//test\Main.java:34: error: method add in class Main cannot be applied to given types;//
//                  add(stream, Collections.emptyList()); // fail//
//                  ^//
//   required: Set<T>,T//
//   found: Set<List<String>>,List<Object>//
//   reason: inferred type does not conform to lower bound(s)//
//     inferred: List<String>//
//     lower bound(s): List<Object>//
//   where T is a type-variable://
//     T extends Object declared in method <T>add(Set<T>,T)//
//1 error/

Is this supposed to work ?


Thanks

Denis

//

-- 
Denis Debarbieux
Engineer at INRIA
+33 (0)3.59.35.87.10
Skype: denis.debarbieux