Is this possible in Java: Map<SomeObject, Map<SomeOtherObject>>?

Is this possible in Java: Map<SomeObject, Map<SomeOtherObj开发者_JAVA百科ect>>? I'm trying Map<Integer, Map<String>> am getting an

"Incorrect number of arguments for type Map; it cannot be parameterized with arguments "

error.

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Every Map needs to be parametrized on two types; your second (nested) Map has only one.

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A Map maps keys to values, so Map<String> is incorrect. So you'd need something like Map<String, Object>.

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You need a second argument on your second Map<>. Perhaps you mean Map<Integer, Map<String, String>>?

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No, not really like that. You need to give a type for both Key and Value for the second "inner" Map, this is ok:

Map<SomeObject, Map<SomeOtherObject, Object>>

Just like with the outer Map, where the Key is SomeObject, and Value is the inner Map. So, if you add a value specification for the inner Map is, that would be ok.