Can not resolve dependency tomcat.http.port in <argument>--server.port=${tomcat.http.port}</argument> in POM

I am trying to copy an old POM, and build my own Java Springboot backend. I am learning about controling the build. In the lectureres, in the POM --server.port=${tomcat.http.port} is automatically resolved, but in my POM it is throwing an error. I know I could just define the property earlier, but I think that prevents the code from being dynamic and causes the the test to fail, as I think it is using a random port alloaction.

Here is my 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 http://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>org.example</groupId>
    <artifactId>KorfballWebsite</artifactId>
    <version>1.0-SNAPSHOT</version>
    <organization>
        <name>amigoscode</name>
        <url>https:amigsocode.com</url>
    </organization>

    <properties>
        <maven.compiler.source>19</maven.compiler.source>
        <maven.compiler.target>19</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <docker.username>rsmithuchot1</docker.username>
    </properties>


    <dependencies>
        <!-- Spring Boot Starters -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jdbc</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>

        <!-- Test Dependencies -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-core</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.testcontainers</groupId>
            <artifactId>testcontainers</artifactId>
            <version>1.19.8</version>
        </dependency>

        <dependency>
            <groupId>org.testcontainers</groupId>
            <artifactId>postgresql</artifactId>
            <version>1.19.8</version>
        </dependency>

        <dependency>
            <groupId>org.testcontainers</groupId>
            <artifactId>junit-jupiter</artifactId>
            <version>1.19.8</version>
        </dependency>

        <!-- Database and Other Dependencies -->
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
        </dependency>

        <dependency>
            <groupId>org.flywaydb</groupId>
            <artifactId>flyway-core</artifactId>
        </dependency>

        <dependency>
            <groupId>org.jetbrains</groupId>
            <artifactId>annotations</artifactId>
            <version>17.0.0</version>
        </dependency>

        <dependency>
            <groupId>io.projectreactor</groupId>
            <artifactId>reactor-core</artifactId>
        </dependency>

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.12.0</version>
        </dependency>

        <!-- Java Faker for testing data generation -->
        <dependency>
            <groupId>com.github.javafaker</groupId>
            <artifactId>javafaker</artifactId>
            <version>1.0.2</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <id>pre-integration-test</id>
                        <goals>
                            <goal>start</goal>
                        </goals>
                        <configuration>
                            <arguments>
                                <argument>--server.port=${tomcat.http.port}</argument>
                            </arguments>
                        </configuration>
                    </execution>
                    <execution>
                        <id>post-integration-test</id>
                        <goals>
                            <goal>stop</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            <!-- Other plugins -->
        </plugins>
    </build>


</project>

Can anyone explain why this is not getting pulled in?

Potentially, a missing dependency or configuration.

In order to pull off the random assignment you should also add the build-helper-plugin to your pom file.

Before the declaration of your spring-boot-maven-plugin add

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>build-helper-maven-plugin</artifactId>
    <executions>
      <execution>
        <id>reserve-tomcat-port</id>
        <goals>
          <goal>reserve-network-port</goal>
        </goals>
        <phase>process-resources</phase>
        <configuration>
          <portNames>
            <portName>tomcat.http.port</portName>
          </portNames>
        </configuration>
      </execution>
    </executions>
  </plugin>

That should allow you to assign that random port for the integration tests.