custom hashmap in java

follows: The relevant code is as follows: By default, the traversal mode of LINKEDHASHMAP is insert mode, and if you want to explicitly specify a get read mode, set the parameter of//its constructor to true, (false means insert mode) Linkedhashmap Linkedhashmap = new Linkedhashmap ((float) 0.75,true); Linkedhashmap.put ("Name", "Louis"); Linkedhashmap.put ("Age", "the"); Linkedhashmap.put ("Sex", "male"); Linkedhashmap.get ("name");//g

Hashtable extends Dictionary implements Mappublic class HashMap extends Abstractmap implements MapSecondThe methods in Hashtable are synchronous, and the methods in HashMap are not synchronized by default. In the context of multi-threaded concurrency, you can use Hashtable directly, but to use hashmap, you need to increase the synchronization process.ThirdIn Ha

The collection package is the most commonly used package in Java, and it is most commonly used with implementation classes for collection and map two interfaces, where collection is used to hold multiple single objects, and map is used to store key-value pairs in key-value form. There are two types of interfaces commonly used in collection: List and set, the most obvious difference is that the list supports placing duplicate objects, and set does not

, the also look at Concurrenthashmap.In short, unsynchronized to be faster, but in view of Hashtable this concept in the interview than HashMap to come more, so in the face of the test is still used Hashtable bar, in the project development I have always used HashMap.REF:http://blog.csdn.net/steedhorse/article/details/6892569Http://stackoverflow.com/questions/355089/stringbuilder-and-stringbuffer-in-javaHttp://vanillajava.blogspot.de/2013/04/why-synch

Java HashMap source code parsing 1 HashMap First, let's look at how the API documentation describes: Implementation of the Map interface based on the hash table. This implementation provides all optional ing operations and allows the use of null values and null keys. (The HashMap class is roughly the same as tha

Turn from: http://www.cnblogs.com/fczjuever/archive/2013/04/07/3005997.html 1. Elaborates In the Java map Traversal way, many articles are recommended to use EntrySet, think it is more efficient than keyset. The reason: The EntrySet method gets all the keys and value sets at a time, and keyset gets only a set of keys, which, for each key, goes to the map to find an extra value, which reduces overall efficiency. So what is the situation? To understand

. Continue to analyze Histo.log, find an online normal machine, generate histo, use the fault machine data minus normal value, get the difference is as follows (Top 10): class instances bytes [B 47404 4275481936 java.util.hashmap$entry 19442009 622144288 java.lang.Long 19711584 473078016 [Ljava.util.hashmap$entry; 239216 164734560 com.taobao.at.dal.comm

It seems that there is no source read today, so come and seeJavathe two kinds of hashmap have a different place, before this, first popularize some basic knowledge of HashMap:(1) The element to be put into HashMap is key-value.(2) The bottom is the hash structure that the previous data structure course talked about.(3) To put elements into the

In the Java world, regardless of class or data, the process of its structure is the key to the logic and performance of the entire program. Because I contacted a question about the coexistence of performance and logic, I began to study this problem. Searched the forum of big and Small, also "Java Virtual machine Specification", "apress,.java.collections." (2001),. Bm.ocr.6.0.shareconnector ", and" thinking

In the Java world, regardless of class or data, the process of its structure is the key to the logic and performance of the entire program. Because I contacted a question about the coexistence of performance and logic, I began to study this problem. Searched the forum of big and Small, also "Java Virtual machine Specification", "apress,.java.collections." (2001),. Bm.ocr.6.0.shareconnector ", and" thinking

Two ways to HashMap traversal in JavaOriginal address: http://www.javaweb.cc/language/java/032291.shtmlThe first type:Map map = new HashMap ();Iterator iter = Map.entryset (). Iterator ();while (Iter.hasnext ()) {Map.entry Entry = (map.entry) iter.next ();Object key = Entry.getkey ();Object val = Entry.getvalue ();}The efficiency is high, must use this kind of wa

Taobao in the intranet to see colleagues posted a CPU was 100% of the online fault, and this happened many times, because the Java language in the concurrency of the use of HashMap caused race Condition, resulting in a dead loop. This thing I have experienced 4, 5 years ago, I thought there was nothing to write, because Java