Often you want to run a software without first cloning or building the sources. In fact, almost any time you download a software from the internet you receive a precompiled release rather than source code.
It is actually not so trivial to obtain such a standalone executable that comes a single file, with all its dependencies included.
Maven comes with powerful mechanisms to build your project to a wholesome Java Archive (JAR) file. In this case, all dependencies are included - however the customer still needs a Java Runtime Environment (JRE).
Note: It is also possible to include the JRE dependencies themselves. However, for simplicity this is not covered in this guide. Additional info on true platform specific standalones e.g. Mac can be found here.
Creating a JAR with all dependencies
Once more this is a goal best achieved by help of targeted plugins. Similar to the Direct Run module we needed to provide a pointer to the desired launcher class, we need to tell the jar-creating plugin about the entry point to our code.
Below are three snippets for Vanilla, Spring Boot and JavaFX projects. There are many more plugins for further frameworks, but this selection should give you a good illustration of the procedure.
- Add the desired plugin to your
- Then compile / build a self contained jar with:
mvn clean package
- Finally run the produced jar:
java -jar target/whatever.jar
<plugin> <artifactId>maven-assembly-plugin</artifactId> <executions> <execution> <phase>package</phase> <goals> <goal>single</goal> </goals> </execution> </executions> <configuration> <archive> <manifest> <addClasspath>true</addClasspath> <mainClass>eu.kartoffelquadrat.zoo.Launcher</mainClass> </manifest> </archive> <descriptorRefs> <descriptorRef>jar-with-dependencies</descriptorRef> </descriptorRefs> <finalName>AcquireBanker</finalName> <appendAssemblyId>false</appendAssemblyId> </configuration> </plugin>
<plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <configuration> <fork>true</fork> <mainClass>eu.kartoffelquadrat.zoo.RestLauncher</mainClass> </configuration> <executions> <execution> <goals> <goal>repackage</goal> </goals> </execution> </executions> </plugin>
<plugin> <artifactId>maven-shade-plugin</artifactId> <version>3.4.0</version> <executions> <execution> <phase>package</phase> <goals> <goal>shade</goal> </goals> <configuration> <transformers> <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer"> <mainClass>eu.kartoffelquadrat.javafxhelloworld.SuperLauncher </mainClass> </transformer> </transformers> </configuration> </execution> </executions> </plugin>