Java Hashtable class is an implementation of hash table data structure. It is very much similar to HashMap but it is synchronized while HashMap is not.
先附源码:package java.util;import java.io.*;/** * This class implements a hash table, which maps keys to values. Any * non-null object can be used as a ke
Hashtableissynchronized.Ifa thread-safeimplementationisnotneeded, itisrecommendedtouse HashMapinplaceofHashtable.Ifa thread-safe highly-concurrentimplementationisdesired,thenitisrecommendedtouse java.util.concurrent.ConcurrentHash
java中hashtable和hashmap HashMap、HashTable区别。 1、HashMap线程不安全,HashTable线程安全; 2、HashMap的键和值都允许null值存在,而HashTable不允许; 3、HashMap的效率高于Hashtable AI检测代码解析 * Hash table based implementation of the <tt>Map</tt> interface. This * implementation provides all of ...
简介:Java集合简单了解——基于JDK1.8中LinkedHashMap、TreeMap、Hashtable、Properties的实现原理 文章目录: 1.LinkedHashMap 源码中的注释部分 2.TreeMap 3.Hashtable 4.Properties 1.LinkedHashMap 1.1源码中的注释部分 * <p>Hash table and linked list implementation of the <tt>Map</tt> interface, ...
* address of the object into an integer, but this implementation * technique is not required by the * Java™ programming language.) 这段话是说,hashCode方法由于非常实用,所以被定义在Object类中。它为不同的对象返回不同的整数值。它的内部实现机理,通过底层的native方法将内存地址映射为一个整数值。
As of the Java 2 platform v1.2, this class was retrofitted to implement the Map interface, making it a member of the Java Collections Framework. Unlike the new collection implementations, Hashtable is synchronized. If a thread-safe implementation is not needed, it is recommended to use HashMap...
public V put(K key, V value) { return putVal(key, value, false); } /** Implementation for put and putIfAbsent */ final V putVal(K key, V value, boolean onlyIfAbsent) { if (key == null || value == null) throw new NullPointerException(); int hash = spread(key.hashCode()); ...
collection implementations,Hashtableis synchronized. If a thread-safe implementation is not needed, it is recommended to useHashMapin place ofHashtable. If a thread-safe highly-concurrent implementation is desired, then it is recommended to usejava.util.concurrent.ConcurrentHashMapin place ofHash...
The exact details as to when and whether the rehash * method is invoked are implementation-dependent.<p> * * Generally, the default load factor (.75) offers a good tradeoff between * time and space costs. Higher values decrease the space overhead but * increase the time cost to look up...