@SpringBootApplication Not found error coming on module

Question

I am creating microservice application. for which we have a pom in the project. Under this we have multiple modules. I am using Java11 and spring 2.5.4.

below is my pom. from this all the modules will get versions. Its packaging is pom.

<?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>
    <modules>
        <module>twitter-to-kafka-service</module>
    </modules>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.5.4</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.microservices.demo</groupId>
    <artifactId>microservices-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>microservices-demo</name>
    <description>Microservices demo project for Spring Boot</description>
    <packaging>pom</packaging>

    <properties>
        <java.version>11</java.version>
        <spring-boot.version>2.5.4</spring-boot.version>
        <maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
        <twitter4j.version>4.0.7</twitter4j.version>
        <lombok.version>1.18.16</lombok.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
                <version>${spring-boot.version}</version>
            </dependency>

            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <version>${spring-boot.version}</version>
                <scope>test</scope>
                <exclusions>
                    <exclusion>
                        <groupId>org.junit.vintage</groupId>
                        <artifactId>junit-vintage-engine</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>

            <!-- https://mvnrepository.com/artifact/org.twitter4j/twitter4j-stream -->
            <dependency>
                <groupId>org.twitter4j</groupId>
                <artifactId>twitter4j-stream</artifactId>
                <version>${twitter4j.version}</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.version}</version>
                <scope>provided</scope>  <!-- only for compile time-->
            </dependency>


        </dependencies>

    </dependencyManagement>



    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>${maven-compiler-plugin.version}</version>
                <configuration>
                    <release>11</release>
                </configuration>
            </plugin>
        </plugins>
        <pluginManagement>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <version>${spring-boot.version}</version>
                </plugin>
            </plugins>
        </pluginManagement>

    </build>

</project>

Under this project I created one module for which pom is the below.

<?xml version="1.0" encoding="UTF-8"?>
<!--suppress MavenModelInspection, MavenModelInspection -->
<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>microservices-demo</artifactId>
        <groupId>com.microservices.demo</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>twitter-to-kafka-service</artifactId>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.twitter4j</groupId>
            <artifactId>twitter4j-stream</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <scope>provided</scope>  <!-- only for compile time-->
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <properties>
        <maven.compiler.source>15</maven.compiler.source>
        <maven.compiler.target>15</maven.compiler.target>
    </properties>

</project>

Now I am creating main class from where our application will begin. so When i am doing @SpringBootApplication it is saying not found. I am really not sure what I am missing.

I need your help to resolve the same as i am just starting it and got stuck. Please help me on the same.

Answer 1

You are using IntelliJ IDEA and did not update the pom information (Icon in the uppoer right with small 'm' symbol.)

Therefore the dependencies are not resolved properly.

Besides I suggest to use a single module project for spring boot applications, if there is no real requirement to do otherwise.