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Object
is the superclass of all classes. It is used in data structures
where value of data are not important, such as
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Number and its subclasses . And you may want to find out which
are final and which can be extended.
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Comparable
is an interface that defines one method compareTo(Object). It is
used for data structures that exploit order of data, such as
Priority Queue. It is implemented by various data types such as
Integer, Double, etc..
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interfaces (such as Set and Map) for dealing wiht elements and their groups
.
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Dictionary
is an abstract class with many abstract methods to be implemented.
Those methods deal with access to elements in the dictionary.