Multiple shadowJar tasks

[sergiofagostinho]

Hi,

I would like to have to multiple shadowJar tasks in my build.gradle. Namely, I would like to have different JAR names for each task. Here is what I've done:

shadowJar {
    mergeServiceFiles()
}

task shadowJar2(type: com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar) {
    mergeServiceFiles()
    archiveName = 'foo.jar'
}

The thing is, when I run the "shadowJar2" task, the "foo.jar" it produces includes only the manifest, no code. What's the correct way to do this?

P.S.: another person has posted a similar question on StackOverflow.

[johnrengelman]

There is a bunch of convention based configuration that happens to the built in shadowJar task. When you create your own task of that type that convention is not applied to the task, so you'll have to manually configure it. You can see what is happening here: https://github.com/johnrengelman/shadow/blob/master/src/main/groovy/com/github/jengelman/gradle/plugins/shadow/ShadowJavaPlugin.groovy#L38-L63

[sergiofagostinho]

Thanks for the prompt reply.

Humm... this seems a little too complex for what I need.

I've used the following workaround:

shadowJar {
    mergeServiceFiles()
    archiveName = System.properties.getProperty('archiveName')
}

It's not so elegant as it makes me add a -DarchiveName=foo.jar parameter, but it does the job.

[johnrengelman]

You only need a couple pieces:

task shadowJarFoo(type: ShadowJar) {
  archiveName = 'foo.jar'
  from sourceSets.main.output //tells the task to include the project code
  configurations = [ configurations.runtime ] //tells the task to shadow in the jars files in the 'runtime' scope
}

that would get you the majority of the solution. This is the same configuration that you would have to perform if you were adding a custom jar or zip task to your project.

[pavolloffay]

I get com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar_Decorated cannot be cast to java.lang.Class when I define shadowJarFoo from the comment above.

[amardeep]

Based on couple of issues and stack overflow questions, it seems people would like to easily create multiple shadow jars. In my case, i have a directory with multiple java files with main function, and would like to create multiple executable jars. Could you considering adding a task which applies the same configuration which would happen if i added shadowjar to a module with "application" plugin instead of requiring manual configuration each time?

[daviddking]

If you want to create multiple executable shadow JARs with the same class files but different main class entries in the manifest, you can do this:

shadowJar {
  mergeServiceFiles()
}

task shadowJar2(type: Jar, dependsOn: shadowJar) {
  archiveName = 'foo2.jar'
  manifest {
      attributes('Main-Class': 'org.foo.Foo2')
  }
  from zipTree(shadowJar.archivePath)
}

task shadowJar3(type: Jar, dependsOn: shadowJar) {
  archiveName = 'foo3.jar'
  manifest {
      attributes('Main-Class': 'org.foo.Foo3')
  }
  from zipTree(shadowJar.archivePath)
}

[EiConstantin]

I get com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar_Decorated cannot be cast to java.lang.Class when I define shadowJarFoo from the comment above.

I had this issue as well and there are two options to fix this:

1. Specify the full path:

task shadowJarFoo(type: com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar) {
    // ...
}

2. Import the class before specifying the task:

import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
task shadowJarBar(type: ShadowJar) {
    // ...
}

[ph4r05]

In my case I had to add configuration runtimeClasspath instead of runtime (Gradle 6.6)

task shadowJarReloc(type: com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar) {
    group 'shadow'    
    from(project.convention.getPlugin(JavaPluginConvention).sourceSets.main.output)
    configurations = [ project.configurations.runtimeClasspath ]
    exclude('META-INF/INDEX.LIST', 'META-INF/*.SF', 'META-INF/*.DSA', 'META-INF/*.RSA')
}

[keilhofer]

Thank you for your solution. As convention is now deprecated one can use
from(project.extensions.findByType(JavaPluginExtension.class).sourceSets.main.output)
instead of
from(project.convention.getPlugin(JavaPluginConvention).sourceSets.main.output)

[alexanderankin]

There is a bunch of convention based configuration that happens to the built in shadowJar task. When you create your own task of that type that convention is not applied to the task, so you'll have to manually configure it. You can see what is happening here: https://github.com/johnrengelman/shadow/blob/master/src/main/groovy/com/github/jengelman/gradle/plugins/shadow/ShadowJavaPlugin.groovy#L38-L63

that link was this as of march 14 when the quoted comment was posted: https://github.com/johnrengelman/shadow/blob/b886a34f34f520f05c783e12c11c4fb9fb2804e3/src/main/groovy/com/github/jengelman/gradle/plugins/shadow/ShadowJavaPlugin.groovy#L38-L64

[akshayamaldhure]

As per https://imperceptiblethoughts.com/shadow/custom-tasks/, defining a custom shadowJar task like this helped me.

// Shadowing Test Sources and Dependencies
import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar

task myCustomShadowJarTask(type: ShadowJar) {
...
}