Introduction

What is Spring?

• Spring is a Dependency Injection framework to make Java applications loosely coupled.
• Makes the development of JavaEE applications easier.

What is Reflection API?

• Allows inspect and manipulate classes, methods, fields, constructors at runtime.
• Can work without knowing names at compile time.
• Part of package: java.lang.reflect.
• Key classes: Class, Method, Field, Constructor, Modifier.
• Used in frameworks like Spring, Hibernate, JUnit for dynamic behavior.

Example

@Autowired
private Address address;

field injection with @Autowired is powered by Reflection API.

Reflection = Runtime inspection + manipulation of classes and objects.

Spring Standalone Collection

• A collection (List, Set, Map, or Properties) managed by Spring.
• Injected into a Spring bean via XML or Java configuration.
• Standalone means it is defined directly in Spring, without external frameworks.
• Useful for storing multiple values and injecting them into beans.

Transitive dependency in JAVA

A transitive dependency is an indirect dependency included in a project because a direct dependency requires it.

Direct dependency : declared explicitly.

Transitive dependency : pulled in through another dependency.

1. Maven Example:

   Project → Library A → Library B

   Here, Library B is a transitive dependency.

2. In Spring

   spring-core → depends on → spring-jcl.

   if we download spring-core jar file then maven automatically also download spring-jcl jar file.

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