我已定义此方法:
public static <E extends Comparable<E>> NavigableSet<E> navigableSet (List<E> l)
我写的时候:
NavigableSet<Integer> set = Sets.navigableSet(new ArrayList<Integer>());
一切都很好,但是如果我改写这个:
NavigableSet<Integer> set = Sets.navigableSet(new ArrayList<>());
Java无法自动推断Integer类型。我收到以下错误:
error: no suitable method found for navigableSet(ArrayList<Object>)
NavigableSet<Integer> set = Sets.navigableSet(new ArrayList<>());
^
method Sets.<E#1>navigableSet(List<E#1>) is not applicable
(inferred type does not conform to equality constraint(s)
inferred: E#2
equality constraints(s): E#3)
为什么?是什么导致Java无法做出正确的推断?
我的Java版本是:
openjdk 11.0.5 2019-10-15
OpenJDK Runtime Environment AdoptOpenJDK (build 11.0.5+10)
OpenJDK 64-Bit Server VM AdoptOpenJDK (build 11.0.5+10, mixed mode)