banking application using springboot

 

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✅ 1. Spring Web

• Purpose: Enables building web applications, including REST APIs.

• Included in: spring-boot-starter-web

• Provides:

  • Spring MVC (Model-View-Controller)

  • Embedded Tomcat (or Jetty/Undertow)

  • REST controllers with @RestController, @RequestMapping, etc.

✅ 2. MySQL Driver

• Purpose: Acts as a connector (JDBC driver) that allows Java applications to communicate with a MySQL database.

• Maven Dependency: mysql:mysql-connector-java

• Without it, your app can't talk to MySQL.

✅ 3. Spring Data JPA

• Purpose: Simplifies database interactions by abstracting JPA (Java Persistence API) using Spring features.

• Included in: spring-boot-starter-data-jpa

• Provides:

  • Auto generation of SQL queries

  • Repository interfaces like CrudRepository, JpaRepository

  • Pagination, sorting, and custom queries

✅ 4. Lombok

• Purpose: Reduces boilerplate code in Java using annotations.

• Works during compile time

• Common Annotations:

  • @Getter, @Setter

  • @NoArgsConstructor, @AllArgsConstructor

  • @Data (all-in-one)

  • @Builder

✅ Purpose of application.properties in a Maven Spring Boot Project

The application.properties file is a central configuration file used in Spring Boot to define application settings like:

• Database configuration

• Server settings

• Logging levels

• Custom app settings

• Third-party service integrations

src/main/resources/application.properties
 
eg:

 spring.datasource.url=jdbc:mysql://localhost:3306/mydb
spring.datasource.username=root
spring.datasource.password=secret
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

 

✅ Summary of spring.jpa.hibernate.ddl-auto=update

• Purpose: Automatically updates the database schema to match your JPA entity classes.

• Behavior: Adds new columns or tables as needed without deleting data.

• Use Case: Speeds up development by syncing DB schema with code changes.

• ⚠ Not recommended for production – can cause unintended schema changes.

 

Annotation	Purpose
@Entity	Maps class to DB table
@Table(name="accounts")	Sets custom table name
@Id	Marks primary key field
@GeneratedValue(...)	Auto-generates primary key
@Column(name="...")	Maps field to custom column name
@Getter, @Setter	Auto-generates getters and setters (Lombok)
@NoArgsConstructor	Adds no-arg constructor (Lombok)
@AllArgsConstructor	Adds all-args constructor (Lombok)