What is ActiveMQ used for - can we apply messaging concept using a Database?

Question

I looked it up and it used to send messages between 2 systems.
But why? Why wouldn\'t you just use a Database?
There must be some feature that ActiveM

Answer 1

i would like to emphasize the following:

Decoupled : The systems are able to communicate without being connected. Queue lies between systems, one system failure will never affect other as communication is done through Queue. The systems continue to work when they are up.

Recovery support : The messages in Queues itself persisted. The messages can be restored later if Queue fails.

Reliable Communication : Consider a system that process client requests. In normal cases the system receives 100 requests per minute. This system is unreliable when number of request goes beyond average. In such case Queue can manage requests and it can push messages periodically based on system throughput without breaking it.

Asynchronous : Client server communication is non-blocking. Once client sent request to server it can do other operations without waiting for response. When response it received client can handle it anytime.