Java's nine major data structures

Java's nine major data structures

Stack, TreeMap, Vector, ArrayList, LinkedList, HashMap, HashSet, LinkedHashSet, SortedSet, these classes are respectively Implemented the Map and Collection interfaces.

Java Map interface

The keys and values ​​in the Map interface are mapped one by one. Yes Get the value by key.

• Given a key and a value, you can store the value in a Map object. Afterwards, you can access the corresponding value through the key.

• When the accessed value does not exist, the method will throw a NoSuchElementException exception.

• When the type of the object and the element in the Map When the types are incompatible, a ClassCastException will be thrown.

• When a Null object is used in a Map that does not allow the use of Null objects, a NullPointerException will be thrown.

• When trying to modify a read-only Map, an UnsupportedOperationException will be thrown.

Java Collection Interface

##Serial NumberInterface Description1Collection interface 2List interface 3Set4SortedSet 5Map6Map.Entry 7SortedMap8Enumeration

	Collection is the most basic collection interface. A Collection represents a group of Objects, that is, elements of Collection. Java does not provide direct inheritance from Collection. Class, only provides sub-interfaces inherited from (such as List and set). Collection interface stores a set of non-unique, unordered objects.
	The List interface is an ordered Collection. Use this interface to accurately control the insertion of each element. The position of the element in the List can be accessed through the index (the position of the element in the List, similar to the subscript of the array). The index of the first element is 0, and the same element is allowed. List interface stores a set of non-unique, ordered (insertion order) objects.
	Set has exactly the same interface as Collection, but the behavior is different. Set does not save duplicate elements. Set interface stores a unique, unordered set of objects.
	Inherited from Set to save an ordered set.
	The Map interface stores a set of key-value objects and provides a mapping from key to value.
	Describes an element (key/value pair) in a Map. Is an internal class of Map.
	Inherited from Map, keeping Key in ascending order.
	This is a traditional interface and defined method through which you can enumerate (obtain one at a time) elements in a collection of objects. This traditional interface has been replaced by iterators.

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