关于Apache Felix Maven Bundle Plugin：能否用非OSGi依赖构建FATJar OSGi Bundle？

Absolutely! You can use non-OSGi dependencies to build a "fat" OSGi bundle with the Apache Felix Maven Bundle Plugin (BND). This is a super common use case when you need to package all your dependencies—including transitive ones—into a single OSGi JAR. Let me walk you through how to set this up:

• Embed dependencies with the Embed-Dependency directive
  This is the core setting that tells BND to pack specified dependencies directly into your bundle. For non-OSGi dependencies, you can use a wildcard to include all compile and runtime-scoped dependencies (skip test/provided ones that aren't needed at runtime):

  <Embed-Dependency>*;scope=compile|runtime</Embed-Dependency>
  

• Pull in transitive dependencies with Embed-Transitive
  To automatically include all transitive dependencies (no need to list each one manually), add this directive set to true:

  <Embed-Transitive>true</Embed-Transitive>
  

  BND will handle resolving and embedding transitive dependencies even if they aren't OSGi bundles themselves.

• Configure the bundle classpath
  By default, embedded dependencies are placed in a lib/ folder inside your bundle. Make sure your bundle's classpath includes both its own classes and these embedded JARs:

  <Bundle-ClassPath>.,lib/</Bundle-ClassPath>
  

  The . refers to the bundle's root classpath, while lib/ points to the embedded dependency JARs.

• Handle edge cases like conflicts or signed JARs

  • If you hit duplicate class errors, exclude specific dependencies using excludeGroupIds or excludeArtifactIds:

    <Embed-Dependency>*;scope=compile|runtime;excludeGroupIds=org.slf4j</Embed-Dependency>
    

  • If your dependencies are signed JARs, embedding them might break their signatures. You can either re-sign the final bundle, or use inline=true to embed the dependency's classes directly into your bundle's classpath (note: this increases bundle size and requires careful conflict management):

    <Embed-Dependency>*;scope=compile|runtime;inline=true</Embed-Dependency>
    

Example POM Configuration #

Here's a complete snippet of how your Maven plugin setup might look:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.felix</groupId>
            <artifactId>maven-bundle-plugin</artifactId>
            <version>5.1.9</version> <!-- Use the latest stable version -->
            <extensions>true</extensions>
            <configuration>
                <instructions>
                    <Bundle-SymbolicName>${project.groupId}.${project.artifactId}</Bundle-SymbolicName>
                    <Bundle-Version>${project.version}</Bundle-Version>
                    <Bundle-Name>${project.name}</Bundle-Name>
                    <!-- Optional: Add an activator if your bundle needs startup logic -->
                    <!-- <Bundle-Activator>com.your.package.BundleActivator</Bundle-Activator> -->
                    
                    <!-- Embed all compile/runtime dependencies and their transitives -->
                    <Embed-Dependency>*;scope=compile|runtime</Embed-Dependency>
                    <Embed-Transitive>true</Embed-Transitive>
                    
                    <!-- Set the classpath to include root and embedded libs -->
                    <Bundle-ClassPath>.,lib/</Bundle-ClassPath>
                </instructions>
            </configuration>
        </plugin>
    </plugins>
</build>

Once you've set this up, run mvn clean install—you'll get a single OSGi bundle that includes all your non-OSGi dependencies and their transitives, ready to deploy to any OSGi container.

内容的提问来源于stack exchange，提问作者Sergio Rodríguez Calvo