Migrate-from-Spring-Boot-2-to-Spring-Boot-3

Spring Boot 3 requires Java version 17.
Spring Boot 3 uses Spring Framework 6.

Install Java version 17:

Install Java version 17 from the software center.
From Windows go to Edit the system Environment Variables:
Point JAVA_HOME to C:\Program Files\Java\jdk-17.0.2.

Go to the path variable and add the below line:

C:\Program Files\Java\jdk-17.0.2\bin

Go to Command Prompt and run the command java -version to verify the Java version.
In your project, change the java. version to 17 under the properties tab in the pom.xml file.

Migrate Spring Boot 2.7 to Spring Boot 3.1.1

In your project, change the spring-boot-starter-parent version to 3.1.1 in the pom.xml file.

Spring Boot 3.1.1 release there have been changes to bean validation. Javax has been migrated to the Jakarta package in Spring Boot 3.1.1.
Add Spring Doc Open API dependency in the pom.xml file of your project.

<dependency>
    <groupId>org.springdoc</groupId>
    <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId>
    <version>2.1.0</version>
</dependency>

Add the below line to the main class file of your project.

@OpenAPIDefinition(servers = {@Server(url = "${server.servlet.context-path}", description = "Default Server URL")})

Please ensure server.servlet.context-path is already defined in the application.properties file. Add the Below code in the application.properties file for all the environments:

server.forward-headers-strategy=framework

<spring-cloud.version>2022.0.1</spring-cloud.version>

<dependencyManagement>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-dependencies</artifactId>
        <version>${spring-cloud.version}</version>
        <type>pom</type>
        <scope>import</scope>
    </dependency>
</dependencyManagement>

Add the below property in the properties file for spring cloud config:

spring.cloud.compatibility-verifier.enabled=false

Please update the Jacoco plugin with the latest version in the pom.xml file of your project:

<version>0.8.7</version>

URL matching in Spring Boot 3: Spring Boot 3 significantly changed the trailing slash matching configuration option. This option determines whether or not to treat a URL with a trailing slash the same as a URL without one. If we try to access a URL with a trailing slash, we will receive a 404 error unless the controller is specifically set up to handle URLs with a trailing slash.