Maven技术问题：为何下述pom.xml文件生成空Jar包？

Let's break down the common reasons why your Maven project is generating an empty JAR, based on the partial pom.xml you shared and typical Maven pitfalls:

1. Missing or Misconfigured Source/Resource Directories #

Maven defaults to looking for source code in src/main/java and resources in src/main/resources. If your project's code isn't in these standard paths, and you haven't explicitly configured the <sourceDirectory> or <resources> sections in your build block, Maven won't find any content to package into the JAR.

Check if your project structure aligns with Maven conventions, or add a custom build configuration if needed:

<build>
    <sourceDirectory>src/your-custom-java-dir</sourceDirectory>
    <resources>
        <resource>
            <directory>src/your-custom-resource-dir</directory>
        </resource>
    </resources>
</build>

2. Parent POM Overriding Build Configuration #

Your project inherits from EOParent, which might have a maven-jar-plugin configuration that's excluding all content, or altering how the JAR is assembled. For example, if the parent POM has something like this, it would result in an empty JAR:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-jar-plugin</artifactId>
    <configuration>
        <includes>
            <include>nonexistent-path/**</include>
        </includes>
    </configuration>
</plugin>

Inspect the parent pom.xml to see if any build plugins are modifying the packaging behavior, and override them in your project's build/plugins section if necessary.

3. Incorrect Packaging Type #

If your project is intended to be a POM (aggregator or parent) but you didn't set <packaging>pom</packaging>, Maven will default to jar packaging. But since a POM project has no source code, it will generate an empty JAR. Double-check if your module should actually be a POM type, or if you need to add code/resources to it.

4. No Compiled Classes or Resources #

It's possible that your project simply has no source code (.java files) in the expected directories, or the compilation failed silently. Run mvn clean compile and check the target/classes directory — if it's empty, that confirms Maven isn't finding anything to compile. Fix the source path or add actual code to your project.

5. Plugin Execution Issues #

Sometimes, plugins like maven-compiler-plugin might be misconfigured (e.g., wrong Java version that fails compilation without errors) or skipped, leading to no classes being generated. Run mvn clean package -X to enable debug logging, which will show you exactly what Maven is doing during the packaging phase — look for lines related to compilation and JAR assembly to spot the issue.

内容的提问来源于stack exchange，提问作者CrazySynthax