Resolving Maven JAR Packaging and Dependency Issues for Third‑Party Consumption

The author encountered a requirement to deliver a utility JAR to a third‑party that could not access the private repository, leading to import failures and missing dependencies.

1. Maven common commands – A quick reference of frequently used Maven goals such as clean , validate , compile , test , package , install , verify , site , and deploy is provided.

2. Unable to import after packaging – After building the project with mvn package , the generated JAR could be copied to the third‑party's libs directory and referenced with systemPath , but the IDE still reported import errors because the default packaging plugin creates an executable JAR, not a library.

Solution: replace the packaging plugin with the standard maven-compiler-plugin :

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.8.1</version>
    <configuration>
        <source>1.8</source>
        <target>1.8</target>
        <encoding>UTF-8</encoding>
    </configuration>
</plugin>

After rebuilding, the import error disappears, but a new NoClassDefFoundError for org/apache/commons/codec/binary/Base64 appears, indicating a missing transitive dependency.

3. Missing additional JAR dependencies – The original JAR (≈14 KB) does not contain the commons-codec library (≈339 KB). Two approaches are suggested: bundle the dependencies into the JAR or ask the third‑party to add them manually.

Recommended solution: use the maven-assembly-plugin to create a “jar‑with‑dependencies” package.

<dependency>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-assembly-plugin</artifactId>
    <version>3.0.0</version>
</dependency>

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-assembly-plugin</artifactId>
    <version>2.4.1</version>
    <configuration>
        <descriptorRefs>
            <descriptorRef>jar-with-dependencies</descriptorRef>
        </descriptorRefs>
    </configuration>
</plugin>

Running mvn assembly:assembly produces a large JAR (≈15.4 MB) that includes all required dependencies, which can be safely handed to the third‑party without further errors.

The article concludes with reference links to a CSDN blog and the official Maven dependency mechanism guide.