I. Description of the problem

When I use the Maven aggregation project to package the parent project for packaging, I get an error ：Unable to find main class which probably means that the main startup class cannot be found

2. How to Solve

The project contains modules of some tool classes， and the tool class modules do not need us to be started, It is only provided for other interface service references, No need to start means no main startup class, but the pom file of the parent project references the springboot packaging plugin spring-boot-maven-plugin, namely:

 <plugins> 
            <plugin>
                <groupId>org.springframework.boot</ groupId>
                <artifactId>spring-boot-maven-plugin&lt ;/artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId&gt ;
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>

So when packaging, mvn will scan all dependent modules. If it finds that there is no main startup class under a module, it will report an error.

3. Solution

My solution is: Comment out the packaged plugin spring-boot-maven-plugin of the parent project and then package/install it

You can see that the packaging is successful