1Hash map:
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3 -> It is the implementation of map interface.
4 -> It can contain null values and keys.
5 -> It doesn't maintain input order.
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7Map:
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9 -> It is an interface
10 -> Map has two implementation
11 -> Tree Map
12 -> Hash Map
13 -> Tree Map maintains the input order .
14 -> It will not allow any null values.
15 -> Duplicate keys are not allowed in the map
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