[[packaging-executable]]
== Packaging executable archives

The plugin can create executable archives (jar files and war files) that contain all of
an application's dependencies and can then be run with `java -jar`.



[[packaging-executable-jars]]
=== Packaging executable jars

Executable jars can be built using the `bootJar` task. The task is automatically created
when the `java` plugin is applied and is an instance of {boot-jar-javadoc}[`BootJar`].
The `assemble` task is automatically configured to depend upon the `bootJar` task so
running `assemble` (or `build`) will also run the `bootJar` task.



[[packaging-executable-wars]]
=== Packaging executable wars

Executable wars can be built using the `bootWar` task. The task is automatically created
when the `war` plugin is applied and is an instance of {boot-war-javadoc}[`BootWar`].
The `assemble` task is automatically configured to depend upon the `bootWar` task so
running `assemble` (or `build`) will also run the `bootWar` task.



[[packaging-executable-wars-deployable]]
==== Packaging executable and deployable wars

A war file can be packaged such that it can be executed using `java -jar` and deployed
to an external container. To do so, the embedded servlet container dependencies should
be added to the `providedRuntime` configuration, for example:

[source,groovy,indent=0,subs="verbatim"]
----
include::../gradle/packaging/war-container-dependency.gradle[tags=dependencies]
----

This ensures that they are package in the war file's `WEB-INF/lib-provided` directory
from where they will not conflict with the external container's own classes.

NOTE: `providedRuntime` is preferred to Gradle's `compileOnly` configuration as, among
other limitations, `compileOnly` dependencies are not on the test classpath so any
web-based integration tests will fail.



[[packaging-executable-and-normal]]
=== Packaging executable and normal archives

By default, when the `bootJar` or `bootWar` tasks are configured, the `jar` or `war`
tasks are disabled. A project can be configured to build both an executable archive
and a normal archive at the same time by enabling the `jar` or `war` task:

[source,groovy,indent=0,subs="verbatim"]
----
include::../gradle/packaging/boot-jar-and-jar.gradle[tags=enable-jar]
----

To avoid the executable archive and the normal archive from being written to the same
location, one or the other should be configured to use a different location. One way to
do so is by configuring a classifier:

[source,groovy,indent=0,subs="verbatim"]
----
include::../gradle/packaging/boot-jar-and-jar.gradle[tags=classifier]
----

[[packaging-executable-configuring]]
=== Configuring executable archive packaging

The {boot-jar-javadoc}[`BootJar`] and {boot-war-javadoc}[`BootWar`] tasks are subclasses
of Gradle's `Jar` and `War` tasks respectively. As a result, all of the standard
configuration options that are available when packaging a jar or war are also available
when packaging an executable jar or war. A number of configuration options that are
specific to executable jars and wars are also provided.


[[packaging-executable-configuring-main-class]]
==== Configuring the main class

By default, the executable archive's main class will be configured automatically by
looking for a class with a `public static void main(String[])` method in directories on
the task's classpath.

The main class can also be configured explicitly using the task's `mainClass` property:

[source,groovy,indent=0,subs="verbatim"]
----
include::../gradle/packaging/boot-jar-main-class.gradle[tags=main-class]
----

Alternatively, if the {application-plugin}[`application` plugin] has been applied
its `mainClassName` project property can be used:

[source,groovy,indent=0,subs="verbatim"]
----
include::../gradle/packaging/application-plugin-main-class.gradle[tags=main-class]
----

Lastly, the `Start-Class` attribute can be configured on the task's manifest:

[source,groovy,indent=0,subs="verbatim"]
----
include::../gradle/packaging/boot-jar-manifest-main-class.gradle[tags=main-class]
----



[[packaging-executable-configuring-excluding-devtools]]
==== Excluding Devtools

By default, Spring Boot's Devtools module,
`org.springframework.boot:spring-boot-devtools`, will be excluded from an executable jar
or war. If you want to include Devtools in your archive set the `excludeDevtools`
property to `false`:

[source,groovy,indent=0,subs="verbatim"]
----
include::../gradle/packaging/boot-war-include-devtools.gradle[tags=include-devtools]
----



[[packaging-executable-configuring-unpacking]]
==== Configuring libraries that require unpacking

Most libraries can be used directly when nested in an executable archive, however certain
libraries can have problems. For example, JRuby includes its own nested jar support which
assumes that `jruby-complete.jar` is always directly available on the file system.

To deal with any problematic libraries, an executable archive can be configured to unpack
specific nested jars to a temporary folder when the executable archive is run. Libraries
can be identified as requiring unpacking using Ant-style patterns that match against
the absolute path of the source jar file:

[source,groovy,indent=0,subs="verbatim"]
----
include::../gradle/packaging/boot-jar-requires-unpack.gradle[tags=requires-unpack]
----

For more control a closure can also be used. The closure is passed a `FileTreeElement`
and should return a `boolean` indicating whether or not unpacking is required.



[[packaging-executable-configuring-launch-script]]
==== Making an archive fully executable

Spring Boot provides support for fully executable archives. An archive is made fully
executable by prepending a shell script that knows how to launch the application. On
Unix-like platforms, this launch script allows the archive to be run directly like any
other executable or to be installed as a service.

To use this feature, the inclusion of the launch script must be enabled:

[source,groovy,indent=0,subs="verbatim"]
----
include::../gradle/packaging/boot-jar-include-launch-script.gradle[tags=include-launch-script]
----

This will add Spring Boot's default launch script to the archive. The default launch
script includes several properties with sensible default values. The values can be
customized using the `properties` property:

[source,groovy,indent=0,subs="verbatim"]
----
include::../gradle/packaging/boot-jar-launch-script-properties.gradle[tags=launch-script-properties]
----

If the default launch script does not meet your needs, the `script` property can be used
to provide a custom launch script:

[source,groovy,indent=0,subs="verbatim"]
----
include::../gradle/packaging/boot-jar-custom-launch-script.gradle[tags=custom-launch-script]
----



[[packaging-executable-configuring-properties-launcher]]
==== Using the `PropertiesLauncher`

To use the `PropertiesLauncher` to launch an executable jar or war, configure the task's
manifest to set the `Main-Class` attribute:

[source,groovy,indent=0,subs="verbatim"]
----
include::../gradle/packaging/boot-war-properties-launcher.gradle[tags=properties-launcher]
----
