Portable Service Abstraction(PSA) is an abstract structure to provide access to technology in a consistent way regardless of changes in the environment. It's also called a well-made interface. Thanks to PSA, software engineers can easily change specific technologies such as WAS, JDBC, and so on. Here is is the famous Spring Triangle figure.

Here are some explanations on Aspect Oriented Programming or AOP. Simply put, it's a paradigm called seperation of concerns. It divides concerns into two parts. The one is crosscutting of concerns, and the other one is core concerns. It really increases the flexibility of services by altering their behaviors without affecting its business logics. What is AOP? AOP(Aspect Oriented Programming) is ..

Spring Bean is nothing special, any object in the Spring framework that we initialize through Spring container is called Spring Bean. Any normal Java POJO class can be a Spring Bean if it’s configured to be initialized via container by providing configuration metadata information. (Link)

There're some important concepts in Spring Framework. The following contents are from https://www.baeldung.com/inversion-control-and-dependency-injection-in-spring. 1. Inversion of Control Inversion of Control is a principle in software engineering which transfers the control of objects or portions of a program to a container or framework. In contrast with traditional programming, in which our c..

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