Include JDBC driver for Postgres in the JAR fo my simple demo app driven by Maven

Question

How to make Maven include the JDBC driver for Postgres inside my app's .jar file?

I added this dependency element to the <dependencies> element in my POM.

<!-- https://mvnrepository.com/artifact/org.postgresql/postgresql -->
<dependency>
  <groupId>org.postgresql</groupId>
  <artifactId>postgresql</artifactId>
  <version>42.2.8</version>
</dependency>

The IntelliJ IDE shows the driver was successfully downloaded, as it is listed in the "External Libraries" item of my Project pane. And my code can use the JDBC classes such as PGSimpleDataSource.

When I build, if I look inside the resulting .jar file, there is no JDBC driver included.

My project is driven by Maven, using the maven-archetype-quickstart archetype. I did update all the version numbers within the POM to the latest. My only other change was to add the following to get the manifest file of the JAR to specify a main class.

                    <configuration>
                        <archive>
                            <manifest>
                                <mainClass>work.basil.example.App</mainClass>
                            </manifest>
                        </archive>
                    </configuration>

I thought that Maven by default would bundle all dependencies inside the resulting JAR file. That is the behavior I have seen in building Vaadin web apps. Is that not the case more generally? Or is the JDBC driver special and being omitted for some reason.

If it helps, here is the entire 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>org.example</groupId>
    <artifactId>tryjdbc</artifactId>
    <version>1.0-SNAPSHOT</version>

    <name>tryjdbc</name>
    <description>A simple tryjdbc.</description>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>13</maven.compiler.source>
        <maven.compiler.target>13</maven.compiler.target>
    </properties>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.junit.jupiter/junit-jupiter -->
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter</artifactId>
            <version>5.6.0-M1</version>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.postgresql/postgresql -->
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>42.2.8</version>
        </dependency>


    </dependencies>

    <build>
        <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
            <plugins>
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.1.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-site-plugin</artifactId>
                    <version>3.8.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-project-info-reports-plugin</artifactId>
                    <version>3.0.0</version>
                </plugin>
                <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>3.1.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>3.0.0-M3</version>
                </plugin>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-jar-plugin</artifactId>
                    <version>3.1.2</version>
                    <configuration>
                        <archive>
                            <manifest>
                                <mainClass>work.basil.example.App</mainClass>
                            </manifest>
                        </archive>
                    </configuration>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>3.0.0-M1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>3.0.0-M1</version>
                </plugin>
            </plugins>
        </pluginManagement>
    </build>

    <reporting>
        <plugins>
            <plugin>
                <artifactId>maven-project-info-reports-plugin</artifactId>
            </plugin>
        </plugins>
    </reporting>
</project>

score 2 · Accepted Answer · edited Nov 08 '19 at 07:05

The .war files, such as those you saw in building Vaadin web apps, do include dependencies by default.

In contrast, the .jar files built by Maven do not include any dependencies by default.

You can use a plugin such as maven-shade-plugin to create a shaded jar, which does include the dependencies:

<project>
  ...
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>3.2.1</version>
        <configuration>
          <!-- put your configurations here -->
        </configuration>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>shade</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
  ...
</project>

Further examples can be found on the Apache Maven Shade Plugin project page.

Include JDBC driver for Postgres in the JAR fo my simple demo app driven by Maven

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