Repackaging an application

In order to repackage your application, you simply need to add a reference to the plugin in your pom.xml:

<build>
  ...
  <plugins>
    ...
    <plugin>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-maven-plugin</artifactId>
      <version>1.2.3.RELEASE</version>
      <executions>
        <execution>
          <goals>
            <goal>repackage</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
    ...
  </plugins>
  ...
</build>

The example above repackages a jar or war that is built during the package phase of the Maven lifecycle, including any provided dependencies that are defined in the project. If some of these dependencies need to be excluded, you can use one of the exclude options, see Exclude a dependency for more details.

The original (i.e. non exectuable) artifact is renamed to .original by default but it is also possible to keep the original artifact using a custom classifier.

The plugin rewrites your manifest, and in particular it manages the Main-Class and Start-Class entries, so if the defaults don't work you have to configure those there (not in the jar plugin). The Main-Class in the manifest is actually controlled by the layout property of the boot plugin, e.g.

<build>
  ...
  <plugins>
    ...
    <plugin>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-maven-plugin</artifactId>
      <version>1.2.3.RELEASE</version>
      <configuration>
        <mainClass>${start-class}</mainClass>
        <layout>ZIP</layout>
      </configuration>
      <executions>
        <execution>
          <goals>
            <goal>repackage</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
    ...
  </plugins>
  ...
</build>

The layout property defaults to a guess based on the archive type (jar or war). For the PropertiesLauncher the layout is ZIP (even though the output might be a jar file).

For more detailed examples of how to configure this goal see:

• Custom repackage classifier
• Exclude a dependency

Running the application

The plugin includes a run goal which can be used to launch your application from the command line:

mvn spring-boot:run

By default the application is executed directly from the Maven JVM. If you need to run in a forked process you can use the 'fork' option. Forking will also occur if the 'jvmArguments' or 'agent' options are specified.

If you need to specify some JVM arguments (i.e. for debugging purposes), you can use the jvmArguments parameter, see Debug the application for more details.

By default, any src/main/resources folder will be added to the application classpath when you run the application and any duplicate found in target/classes will be removed. This allows hot refreshing of resources which can be very useful when developing web applications. For example, you can work on HTML, CSS or JavaScipt files and see your changes immediately without recompiling your application. It is also a helpful way of allowing your front end developers to work without needing to download and install a Java IDE.

Of course, if your resources are using tokens that are filtered by Maven, you may want to disable that feature as follows:

<build>
  ...
  <plugins>
    ...
    <plugin>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-maven-plugin</artifactId>
      <version>1.2.3.RELEASE</version>
      <configuration>
        <addResources>false</addResources>
      </configuration>
    </plugin>
    ...
  </plugins>
  ...
</build>

In order to be consistent with the repackage goal, the run goal builds the classpath in such a way that any dependency that is excluded in the plugin's configuration gets excluded from the classpath as well. See Exclude a dependency for more details.