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I agree with everything mccarl says here, but just wanted to add one last point...which is that ConcurrentHashMap not only allows multiple threads to access a shared hash map, it supports them all doing this incredibly efficiently. &nbsp;It's much more efficient to use than using a synchronized HashMap.<br />
<br />
It's really an amazing addition to the Java language.<br />
<br />
Doug
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I agree with everything mccarl says here, but just wanted to add one last point...which is that ConcurrentHashMap not only allows multiple threads to access a shared hash map, it supports them all doing this incredibly efficiently.  It's much more efficient to use than using a synchronized HashMap.

It's really an amazing addition to the Java language.

Doug

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Hashtable also allows multiple threads. So to use ConcurrentHashMap &nbsp;do we need Hash map for sure. Cannot we use ConcurrentHashMap &nbsp;independently. Is there is any simple example on ConcurrentHashMap usage. please advise
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Hashtable also allows multiple threads. So to use ConcurrentHashMap  do we need Hash map for sure. Cannot we use ConcurrentHashMap  independently. Is there is any simple example on ConcurrentHashMap usage. please advise

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I read this interesting link <br />
<a href="http://blog.manishchhabra.com/2012/08/the-5-main-differences-betwen-hashmap-and-hashtable/" rel="ugc">http://blog.manishchhabra.com/2012/08/the-5-main-differences-betwen-hashmap-and-hashtable/</a>
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I read this interesting link
http://blog.manishchhabra.com/2012/08/the-5-main-differences-betwen-hashmap-and-hashtable/ [http://blog.manishchhabra.com/2012/08/the-5-main-differences-betwen-hashmap-and-hashtable/]

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<div class="content wysiwyg-content">
Hi,<br />
<br />
How is ConcurrentHashMap different from Map and HashMap. Waht are advantages, disadvantages, practical uses of each of them. what is ConcurrentModificationExce<wbr />ption.<br />
<br />
<br />
please advise<br />
Any links resources ideas highly appreciated. Thanks in advance
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Hi,

How is ConcurrentHashMap different from Map and HashMap. Waht are advantages, disadvantages, practical uses of each of them. what is ConcurrentModificationException.


please advise
Any links resources ideas highly appreciated. Thanks in advance

concurrenthasmap and ConcurrentModificationException

Java is a platform-independent, object-oriented programming language and run-time environment, designed to have as few implementation dependencies as possible such that developers can write one set of code across all platforms using libraries. Most devices will not run Java natively, and require a run-time component to be installed in order to execute a Java program.

Java

Java Enterprise Edition (Java EE) is a specification defining a collection of Java-based server and client technologies and how they interoperate. Java EE specifies server and client architectures and uses profiles to define technology sets targeted at specific classes of applications. All Java EE profiles share a set of common features, such as naming and resource injection, packaging rules and security requirements.

Java EE

JavaServer Pages (JSP) allow the development of dynamically generated web pages. It uses the Java programming language; JSP pages are translated into servlets at runtime, with each servlet being cached and reused until the JSP is modified. JSP allows Java code to be interleaved with static web markup content, so the resulting page can be compiled and executed on the server to deliver the content.