Creating POM Files
Now that you have the basic configuration shared by all modules (project information, compiler configuration, JUnit test configuration, etc.), you need to create the POM files for each of Spring’s modules. In each subdirectory, you will need to create a POM that extends the parent POM.
The following is the POM for the spring-core module. This module is the best to begin with because all of the other modules depend on it.
<parent>
<groupId>com.exist.m2book.migrating</groupId>
<artifactId>spring-parent</artifactId>
<version>2.0-m1-SNAPSHOT</version>
</parent>
<artifactId>spring-core</artifactId>
<name>Spring core</name>
Again, you won’t need to specify the version or groupId elements of the current module, as those values are inherited from parent POM, which centralizes and maintains information common to the project.