build.gradle

plugins {
    id 'java'
    id 'com.github.johnrengelman.shadow' version '7.1.2'
    id 'maven-publish'
}

defaultTasks("shadowJar")

group = 'com.charliejoseph'
version = '1.0.0'

subprojects {
    apply plugin: 'java'
    apply plugin: 'com.github.johnrengelman.shadow'
    apply plugin: 'maven-publish'

    // Add the following block
    plugins.withId('java') {
        java {
            toolchain {
                languageVersion = JavaLanguageVersion.of(8)
            }
        }
    }

    shadowJar {
        archiveFileName.set("${project.name}-exampleplugin-${rootProject.version}.jar")
    }

    repositories {
        mavenCentral()
        maven {
            name = "spigotmc-repo"
            url = "https://hub.spigotmc.org/nexus/content/repositories/snapshots/"
        }
        maven {
            name = "sonatype"
            url = "https://oss.sonatype.org/content/groups/public/"
        }
        maven {
            name = "opencollab-snapshot-repo"
            url = "https://repo.opencollab.dev/main/"
        }
        maven {
            name = "velocity-repo"
            url = "https://nexus.velocitypowered.com/repository/maven-public/"
        }
    }

    processResources {
        def props = [version: rootProject.version]
        inputs.properties props
        filteringCharset 'UTF-8'
        duplicatesStrategy = DuplicatesStrategy.INCLUDE

        filesNotMatching("**/*.zip") {
            expand props
        }
    }
}