Develop Reference

Maven Executable JAR with dependencies

I've got a mvn project that contains a dependency to apache commons-lang3. I managed to generate a manifest.mf for this jar file and it starts via java -jar .jar on my remote server.
However, it does not include any dependencies and I can't figure out why.
This is the pom.xml located in /workspace/ :
<project>
<modelVersion>4.0.0</modelVersion>
<groupId>com.hohmannit.phdev.midi</groupId>
<artifactId>releng</artifactId>
<version>1.0.0-SNAPSHOT</version>
<packaging>pom</packaging>
<properties>
<tycho.version>2.2.0</tycho.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.eclipse.tycho</groupId>
<artifactId>tycho-p2-director-plugin</artifactId>
<version>${tycho.version}</version>
</plugin>
</plugins>
</pluginManagement>
<plugins>
<plugin>
<groupId>org.eclipse.tycho</groupId>
<artifactId>tycho-maven-plugin</artifactId>
<version>${tycho.version}</version>
<extensions>true</extensions>
</plugin>
<!--Enable the replacement of the SNAPSHOT version in the final product configuration-->
<plugin>
<groupId>org.eclipse.tycho</groupId>
<artifactId>tycho-packaging-plugin</artifactId>
<version>${tycho.version}</version>
<executions>
<execution>
<phase>package</phase>
<id>package-feature</id>
<configuration>
<finalName>${project.artifactId}_${unqualifiedVersion}.${buildQualifier}</finalName>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.eclipse.tycho</groupId>
<artifactId>target-platform-configuration</artifactId>
<version>${tycho.version}</version>
<configuration>
<!-- Optional set the Java version your are using-->
<executionEnvironment>JavaSE-11</executionEnvironment>
<environments>
<environment>
<os>linux</os>
<ws>gtk</ws>
<arch>x86_64</arch>
</environment>
<environment>
<os>win32</os>
<ws>win32</ws>
<arch>x86_64</arch>
</environment>
<environment>
<os>macosx</os>
<ws>cocoa</ws>
<arch>x86_64</arch>
</environment>
</environments>
</configuration>
</plugin>
</plugins>
</build>
<modules>
<module>midi</module>
</modules>
</project>
And this is the pom.xml located in /workspace/midi :
<?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>
<groupId>com.hohmannit.phdev</groupId>
<artifactId>midi</artifactId>
<version>0.0.2-SNAPSHOT</version>
<name>midi</name>
<url>http://example.com</url>
<build>
<pluginManagement><!-- lock down plugins versions to avoid using Maven
defaults (may be moved to parent pom) -->
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>prepare-package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>
${project.build.directory}/midi/libs
</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>libs/</classpathPrefix>
<mainClass>
com.hohmannit.phdev.midi.App
</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>3.1.0</version>
</plugin>
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
<configuration>
<release>11</release>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>3.0.0-M5</version>
</plugin>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<version>2.5.2</version>
</plugin>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
</plugin>
<plugin>
<artifactId>maven-site-plugin</artifactId>
<version>3.7.1</version>
</plugin>
<plugin>
<artifactId>maven-project-info-reports-plugin</artifactId>
<version>3.0.0</version>
</plugin>
</plugins>
</pluginManagement>
</build>
<dependencies>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<version>5.4.2</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.11</version>
<scope>compile</scope>
</dependency>
</dependencies>
</project>
The gitlab CI file looks like this:
image: maven:3-jdk-11
variables:
# This will suppress any download for dependencies and plugins or upload messages which would clutter the console log.
# `showDateTime` will show the passed time in milliseconds. You need to specify `--batch-mode` to make this work.
MAVEN_OPTS: "-Dhttps.protocols=TLSv1.2 -Dmaven.repo.local=$CI_PROJECT_DIR/.m2/repository -Dorg.slf4j.simpleLogger.log.org.apache.maven.cli.transfer.Slf4jMavenTransferListener=WARN -Dorg.slf4j.simpleLogger.showDateTime=true -Djava.awt.headless=true"
# As of Maven 3.3.0 instead of this you may define these options in `.mvn/maven.config` so the same config is used
# when running from the command line.
# `installAtEnd` and `deployAtEnd` are only effective with recent version of the corresponding plugins.
MAVEN_CLI_OPTS: "--batch-mode --errors --fail-at-end --show-version -DinstallAtEnd=true -DdeployAtEnd=true"
cache:
paths:
- .m2/repository
default-job:
script:
- mvn test
except:
- tags
release-job:
script:
- mvn clean package
artifacts:
paths:
- /builds/phdev/midi-sequencer/midi/target/*.jar
only:
- tags
When this job runs through, I get a jar file with the following MANIFEST.MF:
Manifest-Version: 1.0
Archiver-Version: Plexus Archiver
Created-By: Apache Maven 3.6.3
Built-By: root
Build-Jdk: 11.0.10
Class-Path: libs/commons-lang3-3.11.jar
Main-Class: com.hohmannit.phdev.midi.App
You can see, that it correctly resolves the dependency to commons-lang and puts it into the manifest. But the actual files are missing.
Anyone knows why?

I think your maven-jar-plugin adding entries to the manifest. however, it is not bundled with the dependencies.
try adding the following plugin
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>fully.qualified.MainClass</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>

maven compilation error : The filename, directory name, or volume label syntax is incorrect

Am compiling my pom.xml file and am getting the below compilation error
Failed to execute goal org.apache.maven.plugins:maven-dependency-plugin:2.5.1:copy-dependencies (copy-dependencies) on project ElasticSearchUtility: Error copying artifact from C:\Users\10641516\.m2\repository\org\apache\lucene\lucene-sandbox\7.1.0\lucene-sandbox-7.1.0.jar to D:\Karthikeyan\ElasticSearch\ElasticSearch_Tesing\target\dependency-
[ERROR] jars\lucene-sandbox-7.1.0.jar: The filename, directory name, or volume label syntax is incorrect
But the required .jar file is available in the specified path.
I have created two java file my maven project one is POJO class and another one is java main class file. I want to make my project as an executable jar file which i want to run externally using java -jar command.
Please find my pom.xml file
<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>
<groupId>ElasticSearchUtility</groupId>
<artifactId>ElasticSearchUtility</artifactId>
<version>1.0.0-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.elasticsearch</groupId>
<artifactId>elasticsearch</artifactId>
<version>6.1.2</version>
</dependency>
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-high-level-client</artifactId>
<version>6.1.2</version>
</dependency>
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>rest</artifactId>
<version>5.1.2</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-eclipse-plugin</artifactId>
<version>2.9</version>
<configuration>
<downloadSources>true</downloadSources>
<downloadJavadocs>false</downloadJavadocs>
</configuration>
</plugin>
<!-- Set a compiler level -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<!-- Make this jar executable -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<excludes>
<exclude>**/log4j.properties</exclude>
</excludes>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>ProjectJar.project.App</mainClass>
<classpathPrefix>dependency-jars/</classpathPrefix>
</manifest>
</archive>
</configuration>
</plugin>
<!-- Copy project dependency -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.5.1</version>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<!-- exclude junit, we need runtime dependency only -->
<includeScope>runtime</includeScope>
<outputDirectory>${project.build.directory}/dependency-
jars/</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</projects>

The sawn off error message:
... D:\Karthikeyan\ElasticSearch\ElasticSearch_Tesing\target\dependency-
suggests that you need to change the outputDirectory configuration of the maven-dependency-plugin to:
<configuration>
<!-- exclude junit, we need runtime dependency only -->
<includeScope>runtime</includeScope>
<outputDirectory>
${project.build.directory}/dependency-jars/
</outputDirectory>
</configuration>
to get rid of the newline in the middle the value.

Java Maven Jasperreport run from Eclipse Ok, from with java - jar JRRuntimeException: Chart theme "eye.candy.sixties" not found

I created a Java program which creates a report with JasperReports.
In one of my JasperReports I use the theme="eye.candy.sixties".
when I run the project from Eclipse in the gui, all is fine, see
However when I build the same project with Maven and run it from the commandline I get the error:
Maven: clean compile assembly:single
Command line: java -jar chartTheme-0.0.1-SNAPSHOT-jar-with-dependencies.jar
Exception in thread "main" net.sf.jasperreports.engine.JRRuntimeException: Chart theme "eye.candy.sixties" not found.
What am I missing, what should I change? Any help welcome!
Source code can be found on Github: ChartTheme
I did include the chart theme dependency in Maven, see the "Maven dependencies list in Eclipse:
and in the code below (pom.xml)
<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>
<groupId>com.lightroomstatistics.samples</groupId>
<artifactId>chartTheme</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>chartTheme</name>
<description>chartTheme</description>
<url>www.lightroomstatistics.com</url>
<organization>
<name>LightroomStatistics</name>
<url>www.lightroomstatistics.com</url>
</organization>
<parent>
<groupId>com.lightroomstatistics.maven</groupId>
<artifactId>lightroomstatistics-parent-pom</artifactId>
<version>1.0.0</version>
</parent>
<properties>
<java.version>1.8</java.version>
<jasperreports.version>6.4.0</jasperreports.version>
<jasperreportsfonts.version>4.0.0</jasperreportsfonts.version>
<maven.compiler.target>1.8</maven.compiler.target>
<maven.compiler.source>1.8</maven.compiler.source>
</properties>
<repositories>
<!-- Needed for Jasperreports chart-themes -->
<repository>
<id>jr-ce-releases</id>
<name>JasperReports CE Releases</name>
<url>http://jaspersoft.jfrog.io/jaspersoft/jr-ce-releases</url>
</repository>
</repositories>
<dependencies>
<dependency>
<groupId>net.sf.jasperreports</groupId>
<artifactId>jasperreports</artifactId>
<version>${jasperreports.version}</version>
</dependency>
<dependency>
<groupId>net.sf.jasperreports</groupId>
<artifactId>jasperreports-fonts</artifactId>
<version>${jasperreportsfonts.version}</version>
</dependency>
<!-- jasperreports-chart-themes -->
<dependency>
<groupId>net.sf.jasperreports</groupId>
<artifactId>jasperreports-chart-themes</artifactId>
<version>${jasperreports.version}</version>
</dependency>
</dependencies>
<build>
<resources>
<resource>
<directory>reports</directory>
<includes>
<include>**/*.*</include>
</includes>
</resource>
<resource>
<directory>data</directory>
<includes>
<include>**/*.*</include>
</includes>
</resource>
</resources>
<plugins>
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
<executions>
<execution>
<id>copy-report-resources</id>
<!-- here the phase you need -->
<phase>validate</phase>
<goals>
<goal>copy-resources</goal>
</goals>
<configuration>
<outputDirectory>${basedir}/target/reports</outputDirectory>
<resources>
<resource>
<directory>reports</directory>
<filtering>true</filtering>
</resource>
</resources>
</configuration>
</execution>
<execution>
<id>copy-data-resources</id>
<!-- here the phase you need -->
<phase>validate</phase>
<goals>
<goal>copy-resources</goal>
</goals>
<configuration>
<outputDirectory>${basedir}/target/data</outputDirectory>
<resources>
<resource>
<directory>data</directory>
<filtering>true</filtering>
</resource>
</resources>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>chartTheme.ChartThemesApp</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>

If you open your built joint-library chartTheme-0.0.1-SNAPSHOT-jar-with-dependencies.jar, you'll realize that the contents of file jasperreports-char-themes-6.4.0.jar/jasperreports_extension.properties are misssing, because they were overriden with the contents of some other jasperreports_extension.properties file also present in your dependencies.
In fact, if you search in the output console after running mvn assembly, you'll find these traces:
[INFO] jasperreports_extension.properties already added, skipping
... which, by the way, is not the only one file skipped at assembly.
So, definitely it's not a good idea to assembly all of these dependencies together, because of the overlaps. At least, not in this way.
I think the first thing you should try is to parametrize the assembly descriptor file to exclude the undesired files priorizing the desired ones, which I presume will be the ones in jasperreports-chart-themes.jar (by the traces in the log you posted).

Thank you for looking into this problem. Little Santi explained to me what was the problem.
Also not liking to have a big JAR, I decided to put all the dependency jar in a separate lib directory / folder. This worked fine.
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>lib/</classpathPrefix>
<mainClass>chartTheme.ChartThemesApp</mainClass>
</manifest>
</archive>
<finalName>${project.name}</finalName>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.5.1</version>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/lib/</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>

Maven - maven-war-plugin to generate jar and install it to maven local repository

I am using maven-war-plugin in my pom.xml to generate a jar file in parallel with my war file in an java web project build. My maven build is creating war and jar files in the target directory. And only war file is installed to local repository. Is there a way to push the jar file created as well to local repository. Below is the snippet of my pom.xml
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<configuration>
<archive>
<addMavenDescriptor>false</addMavenDescriptor>
</archive>
<archiveClasses>true</archiveClasses>
<packagingExcludes>WEB-INF/lib/x*.jar</packagingExcludes>
<webXml>${project.basedir}\src\main\webapp\WEB-INF\web.xml</webXml>
<webResources>
<resource>
<directory>${project.basedir}\src\main\webapp</directory>
<includes>
<include>**/*.*</include>
</includes>
</resource>
</webResources>
</configuration>
</plugin>
Thanks in advance!
pom.xml content:
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.xyz</groupId>
<artifactId>x</artifactId>
<packaging>war</packaging>
<version>1.0.0-SNAPSHOT</version>
<name>x</name>
<url>http://maven.apache.org</url>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<configuration>
<archive>
<addMavenDescriptor>false</addMavenDescriptor>
</archive>
<archiveClasses>true</archiveClasses>
<packagingExcludes>WEB-INF/lib/x*.jar</packagingExcludes>
<webXml>${project.basedir}\src\main\webapp\WEB-INF\web.xml</webXml>
<webResources>
<resource>
<directory>${project.basedir}\src\main\webapp</directory>
<includes>
<include>**/*.*</include>
</includes>
</resource>
</webResources>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>${java-version}</source>
<target>${java-version}</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
<plugin>
<groupId>com.googlecode.addjars-maven-plugin</groupId>
<artifactId>addjars-maven-plugin</artifactId>
<version>1.0.2</version>
<executions>
<execution>
<goals>
<goal>add-jars</goal>
</goals>
<configuration>
<resources>
<resource>
<directory>${project.basedir}/src/main/webapp/WEB-INF/lib</directory>
</resource>
</resources>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>

This is not the right way to use maven. Maven is all about modularity and as a consequence there is a "one project - one artifact" rule (or recommendation). See also this blog if I can't convince you : How to Create Two JARs from One Project (…and why you shouldn't) . It is about multiple jars but the concept is the same.
I think you should restructure your work into having one separate project for the jar, while the others use it as a dependency.

How can I include resources (css, js) from jar using maven assembly?

I have a project which contains shared resources for several sub-projects; i.e. as well as Java code, it contains css and javascript.
My child sub-projects are packaged as jars using the maven assembly plugin. For some reason these do not include the css and js resources from the parent library.
So my question is simple: how can I configure the projects so that this happens? I don't want the child projects to be wars; they are dropwizard (/jetty) projects that run as standalone jars.
EDIT - I should make explicit that the resources are included in the parent project's jar; it's only when assembly (on a child project) includes the jar that they somehow go missing.
Parent pom:
<?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>
<groupId>io.parentproject</groupId>
<artifactId>parentproject</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
...
</dependencies>
<build>
<resources>
<resource>
<directory>src/main/webapp</directory>
</resource>
<resource>
<directory>src/main/resources</directory>
</resource>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.java</include>
<include>**/*.gwt.xml</include>
</includes>
</resource>
</resources>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
<compilerArgument>-proc:none</compilerArgument>
<fork>true</fork>
</configuration>
</plugin>
<plugin>
<artifactId>maven-jar-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<archive>
<manifest>
<addDefaultImplementationEntries>
true
</addDefaultImplementationEntries>
</manifest>
</archive>
</configuration>
</plugin>
...
</plugins>
</build>
</project>
Example child pom:
<?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>
<groupId>io.child</groupId>
<artifactId>child</artifactId>
<version>1.0-SNAPSHOT</version>
<name>Child</name>
<dependencies>
<dependency>
<groupId>io.parentproject</groupId>
<artifactId>parentproject</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
...
</dependencies>
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
</resource>
<resource>
<directory>src/main/webapp</directory>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
<compilerArgument>-proc:none</compilerArgument>
<fork>true</fork>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<archive>
<manifest>
<addDefaultImplementationEntries>
true
</addDefaultImplementationEntries>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.4</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>io.childproject.SomeClass</mainClass>
</manifest>
</archive>
<finalName>${project.artifactId}-${project.version}</finalName>
<appendAssemblyId>false</appendAssemblyId>
</configuration>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>assembly</goal>
</goals>
</execution>
</executions>
</plugin>
...
</plugins>
</build>
</project>

So my question is simple: how can I configure the projects so that this happens? I don't want the child projects to be wars; they are dropwizard (/jetty) projects that run as standalone jars.>
You need to add resource directory in <resource></resource> so that it picks up while building jar
You could either use maven-assembly plugin or configure your pom.xml to have these resources files specified as maven resources, assembly plugin will give you much more flexibility

I ended up using maven shade instead. It's a little more heavyweight than assembly but it does the job.
Still, if anybody knows how to make assembly do this please add an answer.