Java 声明带有泛型的函数以用作查找映射中的值

我做错了什么，但不确定是什么. 试图制作一个查找 map ，为我提供我可以调用的函数.

问题的简单演示:

哦，我是.我是.

public class aa { /** doesn't matter for this example */}

♪Ab.Java♪

public class ab extends aa { /** doesn't matter for this example */}

Helper.java

public static short[] convert(ab foo)
{
  //doesn't matter but eventually returns a short[] i.e.
  return new short[5];
}

private interface aaConverterI
{
  public <T extends aa> short[] method(Function<T, short[]> in);
}

private static Map<String, aaConverterI> bar = new HashMap<>();
static
{
  bar.put("blah", Helper::convert);
}

编译器在Helper::Convert上说是The type Helper does not define convert(Function<T, short[]>) that is applicable here,The method put(String, Helper.aaConverterI) in the type Map<String, aaConverterI> is not applicable for the arguments (String, Helper::convert).

如果我添加一个

static Function<ab, short[]> blahFunction = Helper::convert;

没有抱怨，我可以改变把

bar.put("blah", blahFunction);

这使得编译器只会在PUT上抱怨The method put(String, Helper.aaConverterI) in the type Map<String, Helper.aaConverterI> is not applicable for the arguments (String, Function<ab, short[]>).

我错过了一些东西，但我不确定是什么.try 添加@FunctionalInterface来转换声明，但这并没有改变任何事情.

我遗漏了什么？谢谢!