收集字符集流

Question

我有这个字符集：

Stream<Set<Character>> characterSet

现在，我想将此流转换为简单的字符集，然后执行：

Set<Character> newSet = characterSet.collect(Collectors.toSet());

但是，出现此错误：

Incompatible types. Required Set<Character> but 'collect' was inferred to R: no instance(s) of type variable(s) exist so that Set<Character> conforms to Character inference variable T has incompatible bounds: equality constraints: Character lower bounds: Set<Character>.

我该如何解决？谢谢！

Answer 1

下面给出了一个示例：