generics - What does Map<?, ?> mean in Java?

Question

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

What does Map<?, ?> mean in Java?
I've looked online but can't seem to find any articles on it.

edit : I found this on MP3 Duration Java

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1 Answer

深蓝 · Answer 1 · 2021-10-23T21:27:34+0000

Map<?,?> means that at compile time, you do not know what the class type of the key and value object of the Map is going to be.