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This article introduces you how to analyze the source code of the ConcurrentHashMap collection, the content is very detailed, interested friends can refer to, hope to be helpful to you.

Of all the collection classes we have introduced, only three collection classes, Hashtable, Stack, and Vector, are thread safe, that is, we do not need to add additional code to use in a multithreaded environment. Of course, we can make a non-thread-safe collection class thread-safe by adding additional code. There are two main ways.

Use the synchronized synchronization keyword directly.

The other is to call the synchronizedMap method of the Collections class

The following code creates a thread-safe HashMap collection

In fact, when we are doing multithreaded development, we generally do not use the above implementation if we need to use collections. Instead, we directly use a new collection to implement our logic, which is the ConcurrentHashMap collection we are going to share today. As the name implies, the feature of this collection is to ensure thread safety, in addition, the underlying implementation of the ConcurrentHashMap collection also takes into account performance optimization.

Then let's not talk much nonsense, let's directly analyze the underlying source code of the ConcurrentHashMap collection. First, take a look at the initialization code for the ConcurrentHashMap collection.

The no-parameter constructor of the ConcurrentHashMap collection simply defines an empty method without any implementation. Initialization is very different from other collection classes in one point. Because of the nature of the ConcurrentHashMap collection, thread safety is guaranteed. And we know that if thread safety problems occur when using collections, nine times out of ten, they occur when elements are added and deleted. That is, the corresponding put and remove methods in the collection. So our next focus is to analyze in detail the underlying implementation of the put method and the remove method in the ConcurrentHashMap collection.

Put

Remove

On how to carry out ConcurrentHashMap collection source code parsing is shared here, I hope that the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

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