Implementing Swagger in a Java Spring project

I want to add Swagger to my Spring application. But I can't figure out why it's not working. I found so many solutions for that but for now nothing worked for me.

@EnableSwagger2
@Configuration
public class SpringFoxConfig {
    @Bean
    public Docket api() {
        return new Docket(DocumentationType.SWAGGER_2)
                .select()
                .apis(RequestHandlerSelectors.any())
                .paths(PathSelectors.any())
                .build();
    }
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.0.0</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.portfolio-generator</groupId>
    <artifactId>backend</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>backend</name>
    <description>portfolio generator</description>
    <properties>
        <java.version>19</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-boot-starter</artifactId>
            <version>3.0.0</version>
        </dependency>
        <dependency>
            <groupId>commons-validator</groupId>
            <artifactId>commons-validator</artifactId>
            <version>1.4.1</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

current error:

java.lang.TypeNotPresentException: Type javax.servlet.http.HttpServletRequest not present at java.base/sun.reflect.generics.factory.CoreReflectionFactory.makeNamedType(CoreReflectionFactory.java:117) ~[na:na] at java.base/sun.reflect.generics.visitor.Reifier.visitClassTypeSignature(Reifier.java:125) ~[na:na] at java.base/sun.reflect.generics.tree.ClassTypeSignature.accept(ClassTypeSignature.java:49) ~[na:na] at java.base/sun.reflect.generics.visitor.Reifier.reifyTypeArguments(Reifier.java:68) ~[na:na] at java.base/sun.reflect.generics.visitor.Reifier.visitClassTypeSignature(Reifier.java:138) ~[na:na] at java.base/sun.reflect.generics.tree.ClassTypeSignature.accept(ClassTypeSignature.java:49) ~[na:na] at java.base/sun.reflect.generics.repository.ClassRepository.computeSuperInterfaces(ClassRepository.java:117) ~[na:na] at java.base/sun.reflect.generics.repository.ClassRepository.getSuperInterfaces(ClassRepository.java:95) ~[na:na] at java.base/java.lang.Class.getGenericInterfaces(Class.java:1250) ~[na:na] at org.springframework.core.ResolvableType.getInterfaces(ResolvableType.java:500) ~[spring-core-6.0.2.jar:6.0.2] at org.springframework.core.ResolvableType.as(ResolvableType.java:448) ~[spring-core-6.0.2.jar:6.0.2] at org.springframework.core.ResolvableType.forClass(ResolvableType.java:1048) ~[spring-core-6.0.2.jar:6.0.2] at org.springframework.plugin.core.config.PluginRegistriesBeanDefinitionRegistrar.getTargetType(PluginRegistriesBeanDefinitionRegistrar.java:101) ~[spring-plugin-core-2.0.0.RELEASE.jar:2.0.0.RELEASE] at org.springframework.plugin.core.config.PluginRegistriesBeanDefinitionRegistrar.registerBeanDefinitions(PluginRegistriesBeanDefinitionRegistrar.java:71) ~[spring-plugin-core-2.0.0.RELEASE.jar:2.0.0.RELEASE] at org.springframework.context.annotation.ImportBeanDefinitionRegistrar.registerBeanDefinitions(ImportBeanDefinitionRegistrar.java:86) ~[spring-context-6.0.2.jar:6.0.2] at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.lambda$loadBeanDefinitionsFromRegistrars$1(ConfigurationClassBeanDefinitionReader.java:373) ~[spring-context-6.0.2.jar:6.0.2] at java.base/java.util.LinkedHashMap.forEach(LinkedHashMap.java:729) ~[na:na] at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsFromRegistrars(ConfigurationClassBeanDefinitionReader.java:372) ~[spring-context-6.0.2.jar:6.0.2] at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:148) ~[spring-context-6.0.2.jar:6.0.2] at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitions(ConfigurationClassBeanDefinitionReader.java:120) ~[spring-context-6.0.2.jar:6.0.2] at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:409) ~[spring-context-6.0.2.jar:6.0.2] at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:283) ~[spring-context-6.0.2.jar:6.0.2] at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:344) ~[spring-context-6.0.2.jar:6.0.2] at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:115) ~[spring-context-6.0.2.jar:6.0.2] at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:745) ~[spring-context-6.0.2.jar:6.0.2] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:565) ~[spring-context-6.0.2.jar:6.0.2] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:146) ~[spring-boot-3.0.0.jar:3.0.0] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:730) ~[spring-boot-3.0.0.jar:3.0.0] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:432) ~[spring-boot-3.0.0.jar:3.0.0] at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) ~[spring-boot-3.0.0.jar:3.0.0] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1302) ~[spring-boot-3.0.0.jar:3.0.0] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1291) ~[spring-boot-3.0.0.jar:3.0.0] at com.portfoliogenerator.backend.BackendApplication.main(BackendApplication.java:11) ~[classes/:na] Caused by: java.lang.ClassNotFoundException: javax.servlet.http.HttpServletRequest at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641) ~[na:na] at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188) ~[na:na] at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) ~[na:na] at java.base/java.lang.Class.forName0(Native Method) ~[na:na] at java.base/java.lang.Class.forName(Class.java:495) ~[na:na] at java.base/java.lang.Class.forName(Class.java:474) ~[na:na] at java.base/sun.reflect.generics.factory.CoreReflectionFactory.makeNamedType(CoreReflectionFactory.java:114) ~[na:na] ... 32 common frames omitted

Solution

Spring Boot 3 does not support javax packages. You should replace them with jakarta packages. You can read about version 3 updates here. The swagger dependency in your pom requires classes from javax package, that`s why it is failing.

You can try with Swagger 3:

<dependency>
    <groupId>org.springdoc</groupId>
    <artifactId>springdoc-openapi-ui</artifactId>
    <version>1.2.32</version>
</dependency>

https://www.baeldung.com/spring-rest-openapi-documentation https://www.javainuse.com/spring/boot_swagger3