Further reading: What is middleware?

What is middleware?

Middleware is a variety of components in the program that can be woven, reusable, and have nothing to do with business logic.
Middleware is a large category of basic software and belongs to the category of reusable software. As the name implies, middleware is in the middle of the operating system software and the user's application software. The middleware is above the operating system, the network and the database, and the lower layer of the application software. Its general function is to provide an operating and development environment for the application software at its upper layer, helping users to develop and integrate complex application software flexibly and efficiently.
Among the many definitions of middleware, the more commonly accepted one is expressed by IDC: middleware is an independent system software or service program, distributed application software uses this software to share resources among different technologies, and the middleware The software sits on top of the client server's operating system and manages computing resources and network communications.
Classification: data access middleware, remote call middleware, message middleware, transaction middleware, object middleware.
For example:
1, RMI (Remote Method Invocations, remote invocation)
2, Load Balancing (load balancing, distributing the access load to each server)
3, Transparent Fail-over (transparent failover)
4, Clustering (clustering, using multiple A small server instead of a mainframe)
5, Back-end-Integration (back-end integration, how to integrate legacy systems with existing and newly developed systems)
6, Transaction transaction (global/local) Global transaction (distributed Transaction) Local transaction (transaction within the same database connection)
7, Dynamic Redeployment (dynamic redeployment, deploying a new system without stopping the original system)
8, System Management (system management)
9, Threading (multi-threaded processing)
10, Message-oriented Middleware message-oriented middleware (asynchronous call programming)
11, Component Life Cycle (component life cycle management)
12, Resource pooling (resource pool)
13, Security (security )
14, Caching