Module-info.java won't compile in maven project (Syntax error on token “module”, interface expected)

问题

I am starting a new maven project that should run with Spring Boot (in case that's relevant), and it compiled fine. But then, I decided to start using Java9-modules. So, I had eclipse generate the module-info.java file that looks like this:

module BirdTreeModel {
    exports mjl.familytree.birdtree;

    requires junit;
    requires spring.boot;
    requires spring.boot.autoconfigure;
    requires spring.boot.test;
    requires spring.test;
}

This causes a compile error, however. Eclipse says: "Syntax error on token "module", interface expected". (And when I do a Maven clean install, it says "Compilation failure: ...module not found: junit" and same for modules spring.boot.test and spring.test).

echo %JAVA_HOME% gives C:\Program Files\Java\jdk-12

mvn -version gives:

Apache Maven 3.5.4 (1edded0938998edf8bf061f1ceb3cfdeccf443fe; 2018-06-17T20:33:1
4+02:00)
Maven home: `D:\Programming practice\maven\apache-maven-3.5.4\bin\..`
Java version: 12, vendor: Oracle Corporation, runtime: `C:\Program Files\Java\jdk-12`
Default locale: `en_US`, platform encoding: `Cp1252`.
OS name: "Windows 7", version: "6.1", arch: "AMD64", family: "Windows"

The run configurations of the Maven build of the project are also on JDK-12

My pom looks like this:

<?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>2.1.4.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <groupId>mjl.familytree</groupId>
    <artifactId>birdtree-model-dao</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>birdtree-model-dao</name>
    <description>My family tree program</description>

    <repositories>
        <repository>
            <id>repository.spring.release</id>
            <name>Spring GA Repository</name>
            <url>http://repo.spring.io/release</url>
        </repository>
    </repositories>

    <properties>
        <maven.compiler.source>1.12</maven.compiler.source>
        <maven.compiler.target>1.12</maven.compiler.target>
        <maven.compiler.release>12</maven.compiler.release>
        <java.version>12</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <scope>test</scope>
        </dependency>

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

        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.0</version>
        </dependency>

    </dependencies>

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

来源：https://stackoverflow.com/questions/55797741/module-info-java-wont-compile-in-maven-project-syntax-error-on-token-module