hashmap implementation in java

Java -- HashMap implementation principle, self-implemented simple HashMap, javahashmap There are arrays and linked lists in the data structure to store data. However, the array storage range is continuous, addressing is easy, and insertion and deletion are difficult. The linked list space is discrete, therefore, addre

There are arrays and linked lists in the data structure to achieve the storage, but the array storage interval is continuous, easy to address, insert and delete difficult, and the list of the space is discrete, so addressing difficulties, insert and delete easy.Therefore, combining the advantages of both, we can design a data structure-a hash table (hash table), it is easy to address, insert and delete. In Java, the

A deep understanding of the implementation principles of HashMap in Java HashMap inherits from the abstract class AbstractMap. The abstract class AbstractMap implements the Map interface. The diagram is as follows: Map in Java The interface allows us to use an object as

This article brings the content is about Java in the implementation of the principle of hashmap, there is a certain reference value, there is a need for friends to refer to, I hope you have some help. 1. HashMap Overview:HashMap is a non-synchronous implementation of a hash

Original from: Http://www.cnblogs.com/xwdreamer/archive/2012/06/03/2532832.html1. HashMap Overview:HashMap is a non-synchronous implementation of a hash table-based map interface (Hashtable is like HashMap, the only difference being that the method in Hashtalbe is thread-safe, that is, synchronous). This implementation

Mark, at the same time can be a good combination of hashcode () and the Equals () method, the best way to overwrite the Equals method Hashcode (), to ensure that equals two objects, hashcode also equal, in turn: Hashcode () Unequal, Must be able to introduce equals () also ranged from hashcode () equal, Equals () may or may not be equal. Because HashMap in get, first compare hashcode, then compare Equals,hashcode==equals, both are true, then think th

a method. Because the = = operator does not allow us to overwrite, that is, it restricts our expression. So we replicate the Equals () method to achieve the same purpose of comparing object content. These are not done through the = = operator.The Equals () method of the 2.object class is a comparison rule: Returns True if the two objects are of the same type and the content is consistent, and these classes are:Java.io.file,java.util.date,java.lang.string, packing class (integer,double, etc.)Str

from: Go deep Java Collection Learning Series: the principle of HashMap Reference documents References: Deep Java Collection Learning series: the implementation of the HashMap principle, most of the reference to this blog, only slightly modified I have written:

Deep Java Collection Learning Series: The realization principle of HashMap Reference documents References: Deep Java Collection Learning series: the implementation of the HashMap principle, most of the reference to this blog, only slightly modified I have written:

. * * If current capacity are maximum_capacity, this method does isn't * resize the map, but sets threshold to Integer. Max_value. * This have the effect of preventing future calls. * * @param newcapacity The new capacity, must be a power of; * Must be greater than current capacity unless current * capacity are maximum_capacity (in which case Val UE * is irrelevant). */void Resize (int newcapacity) {entry[] oldtable = table; int oldcapacity = Oldtable.length;

Java HashMap implementation principle source code analysis, javahashmap HashMap is implemented based on the Map interface of the hash table. It provides all the optional ing operations and allows creation of null values and null values. It is not synchronized and the ing sequence is not guaranteed. Next we will record

current* Capacity is maximum_capacity (in which case value* is irrelevant).*/void Resize (int newcapacity) {entry[] oldtable = table;int oldcapacity = Oldtable.length;if (oldcapacity = = maximum_capacity) {threshold = Integer.max_value;Return}entry[] newtable = new Entry[newcapacity];Transfer (newtable);Table = newtable;threshold = (int) (newcapacity * loadfactor);}/*** Transfers all entries from the current table to newtable.*/void Transfer (entry[] newtable) {entry[] src = table;int newcapaci

HashMap is one of the most commonly used tools in the Java development process, and it is often asked during the interview process, which is analyzed by the author's own understanding and numerous information on the web. The author's local JDK version is a 64-bit 1.8.0_171. The following two articles are recommended for reference: Www.cnblogs.com/little-fly/p/7344285.html Monkeysayhi.

code private static final entry[] Empty_table NBSP;N bsp; = new hashmapentry[minimum_capacity >>> 1]; //default constructor Public HashMap () { table = (hashmapentry nbsp; threshold =-1; Forces the invocation to replace Empty_table } Static final int Default_initia l_capacity = 16; Static final float default_load_factor = 0.75f; //default constructor Public HashMap () { this (defa

@ Dream Blog The series of articles on the JDK common container classes ArrayList, LinkedList, HashMap, hashset and other implementation principles in the way of code comments are given (see http://www.cnblogs.com/ dongying/p/4022795.html#3045118 and so on), and I am here in another way to illustrate the main points of its implementation.The implementation princi

There are several options for applying HashMap in a Java multithreaded environment: using thread-safe java.util.Hashtable as an alternative Use the Java.util.Collections.synchronizedMap method to wrap an existing HashMap object as thread-safe. Using the Java.util.concurrent.ConcurrentHashMap class as an alternative, it has very good performance.And the above seve

If anyone asked me to describe HashMap's working mechanism, I would simply answer: "Hash based rules." This sentence is very simple, but to understand this sentence, first we have to understand what is a hash, is not it? What is a hasha hash is simply a unique string that is obtained by applying an algorithm to a variable/object attribute, using this string to determine the uniqueness of the variable/object. A correct hash function must adhere to this guideline. When a hash function is applied

Implementation of HashMap source code in a Java Collection1. Through the above article, we know that the underlying layer of HashSet is implemented by Map. What is Map? How is it implemented at the underlying layer? Next, let's analyze the source code to see the specific structure and implementation. The Map Collection

Concept 1. hash The translation is a hash, and there is also a way to name hash. We should know what we have learned about the data structure. Hash is to use the hash algorithm to obtain a fixed-length output value of any length input value. The hash algorithm is not introduced here. Java hashmap Implementation 1. Storage Structure First, we know that the element

The video introduces the content of HashMap through the following four aspectsFirst, what is HashMapA hash hash converts an arbitrary length into a fixed value by an algorithm (the hash function algorithm). Map: x, y Storage Summary: The value of the hash, then the value to the map, then the value stored in the map of the hashmap rationale1. Can the KEY be empty? Yes, null as a key to store2, if the hash ke