Synchronous vs asynchronous

There are two basic ways of message communication ：

1、 Synchronization mode

Two communication application services must be synchronized , Both services must be running normally . Both sender and receiver must be running at all times , And be ready to communicate with each other at any time .

The sender first sends a request to the receiver , Call it sending messages , The sender will then block its current process , No communication and interaction with other applications , Wait for the response of the receiving program , After receiving the return message from the receiving program, the sending message will continue to run downward , Proceed to the next step of business processing .

2、 Asynchronous way

There is no need to wait online at the same time between two communication applications , Each party only needs to deal with its own business , For example, the sender does not need to log in to the receiver's response after sending the message , You can then deal with other tasks . That is to say, the sender and the receiver are independent of each other , The sender only cares about the sender , The receiver can only receive , There is no need to wait for the other party's response .

Java in JMS It is a typical asynchronous message processing mechanism ,JMS There are two types of messages ： Point to point 、 Release / subscribe .