Hashmap,hashtable,concurrenthashmap comparison under multi-threading (continuous update)

1.hashMap multithreading under put will cause a dead loop, mainly the transfer method will cause a dead loop when expanding.

http://blog.csdn.net/zhuqiuhui/article/details/51849692 (Specific reason)

2.hashTable, using synchornized to ensure thread safety, thread competition in the case of fierce competition, inefficient. When a thread accesses the Hashtable method, the other threads enter the polling or blocking situation.

If thread 1 is adding elements using the Put method, thread 2 cannot put elements nor get elements, so the more intense the competition the lower.

3.concurrentHashmap

Using the lock segmentation technique, it is assumed that the container fragments the data, each section is assigned a lock, and when a line Cheng locks access to one of the data segments, other data segments can be accessed.

Hashmap,hashtable,concurrenthashmap comparison under multi-threading (continuous update)