Shade/shadow in local jar to gradle project

Question

I'm new to gradle and attempting to compile my project, but also "shade in" (as you would in maven) a local jar file.

I'm attempting to use the gradle shadow plugin, however when I run "shadowJar" it doesn't create a jar file with the dependency I wish to shade/shadow in.

How can I properly shade in the contents of a local jar dependency using gradle? Just need someone to point me in the proper direction as I can't find anything about it. Thanks!

Here is my build.gradle:

group 'org.primemc'
version '1.0-SNAPSHOT'

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.github.jengelman.gradle.plugins:shadow:1.2.3'
    }
}

apply plugin: 'java'
apply plugin: 'com.github.johnrengelman.shadow'

sourceCompatibility = 1.8

repositories {
    mavenCentral()

    maven {
        name 'Spigot'
        url 'https://hub.spigotmc.org/nexus/content/groups/public/'
    }

    maven {
        name 'BungeeCord'
        url 'https://oss.sonatype.org/content/repositories/snapshots'
    }

    maven {
        url 'https://nexus.solucorpus.com/repository/maven-all/'
    }
}

dependencies {
    compile 'org.spigotmc:spigot-api:1.8.8-R0.1-SNAPSHOT'    
    compileOnly "org.projectlombok:lombok:1.16.12"

    compile files('./lib/redemptive-core-1.1-SNAPSHOT.jar')
    compile files('./lib/craftbukkit-1.8.8.jar')
    compile 'io.reactivex:rxjava:1.1.6'    

    // Not sure if this is correct or not.. doesn't seem to work.
    shadow files('./lib/redemptive-core-1.1-SNAPSHOT.jar')
}

shadowJar {
    dependencies {
        //Attempting to shade/shadow this jar into the one built.
        include('./lib/redemptive-core-1.1-SNAPSHOT.jar')
    }
}

Answer 1

This worked for me:

shade fileTree(dir: 'lib', include: '<filename>.jar')

Using file() didn't work for me, not sure whether that's due to incorrect syntax, but fileTree did the trick, and also allows for wildcards.