AWS Java Lambda package ways

 There is two ways to make Aws Java Lambda packages, one is to make a uber FAT jar with the shade plugin.

Many people are in two camps on this, as well as it causing major problems with duplicates and needing custom code to make things 'happy'.

An example of this is below

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <configuration>
        <createDependencyReducedPom>false</createDependencyReducedPom>
    </configuration>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>shade</goal>
            </goals>
            <configuration>
                <transformers>
                    <transformer implementation="com.github.edwgiz.maven_shade_plugin.log4j2_cache_transformer.PluginsCacheFileTransformer">
                    </transformer>
                </transformers>
            </configuration>
        </execution>
    </executions>
</plugin>

The second way is to make a zip, it like a .war file in a way and still works, there is more maven configuration of setting up. This also allows a split to occur with the use of Lambda Layers (playing the lib's as a layer) 

<!-- alternative way without needing to use shader -->
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-jar-plugin</artifactId>
    <configuration>
        <finalName>${project.build.finalName}</finalName>
        <archive>
            <manifest>
                <addClasspath>true</addClasspath>
                <classpathPrefix>lib/</classpathPrefix>
                <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
                <addDefaultSpecificationEntries>true</addDefaultSpecificationEntries>
            </manifest>
        </archive>
    </configuration>
</plugin>
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-dependency-plugin</artifactId>
    <version>3.1.2</version>
    <executions>
        <execution>
            <id>copy-dependencies</id>
            <phase>package</phase>
            <goals>
                <goal>copy-dependencies</goal>
            </goals>
            <configuration>
                <includeScope>runtime</includeScope>
                <outputDirectory>${project.build.directory}/lib</outputDirectory>
            </configuration>
        </execution>
    </executions>
</plugin>
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-assembly-plugin</artifactId>
    <version>2.5.4</version>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>single</goal>
            </goals>
            <configuration>
                <descriptors>
                    <descriptor>src/main/assembly/bin.xml</descriptor>
                </descriptors>
                <attach>false</attach>
            </configuration>
        </execution>
    </executions>
</plugin>

<!-- END alternative way without needing to use shader -->

This does require an assembly xml file placed at  src/main/assembly/bin.xml

<assembly>
    <id>aws-lambda-package</id>
    <formats>
        <format>zip</format>
    </formats>
    <includeBaseDirectory>false</includeBaseDirectory>
    <fileSets>
        <fileSet>
            <directory>${project.build.directory}${file.separator}lib</directory>
            <outputDirectory>lib</outputDirectory>
            <useDefaultExcludes>true</useDefaultExcludes>
        </fileSet>
        <!-- copy all classes -->
        <fileSet>
            <directory>${project.build.directory}${file.separator}classes</directory>
            <includes>
                <include>**</include>
            </includes>
            <outputDirectory>${file.separator}</outputDirectory>
        </fileSet>
    </fileSets>

</assembly> 

Upload the zip instead of jar. All is good.

See https://github.com/awslabs/aws-serverless-java-container/commit/22edc6e65dcdefab46145f80c80dcb274b0eedd4