Collection A basic interface that defines the operations that all the classes that maintain collections of objects typically implement.
Set Extends Collection, sets that maintain unique elements. Set interface is defined in terms of the equals operation
SortedSet Extends Set, maintain the elements in a sorted order
Map A basic interface that defines operations that classes that represent mappings of keys to values typically implement我看2吧
Set Extends Collection, sets that maintain unique elements. Set interface is defined in terms of the equals operation
SortedSet Extends Set, maintain the elements in a sorted order
Map A basic interface that defines operations that classes that represent mappings of keys to values typically implement我看2吧
Set need key is uniqueness and not sort orderSort just sort order but not uniquenessSortSet is unique and sort order
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public interface ComparableThis interface imposes a total ordering on the objects of each class that implements it. This ordering is referred to as the class's natural ordering, and the class's compareTo method is referred to as its natural comparison method.
上面是jdk中Comparable接口的文档,也就是按照Comparable中的compareTo方法比较
后出来的顺序是natual order.很显然,答案是2。