paper-plugin-dev

Minecraft Paper Plugin Development — Java 21 & Paper 1.21.x

This skill is a comprehensive reference and rule set that enables Claude to write professional-quality Java 21 plugins for Minecraft Paper servers.

1. PROJECT SETUP

1.1 Gradle (Kotlin DSL) — RECOMMENDED

// settings.gradle.kts
pluginManagement {
    repositories {
        gradlePluginPortal()
        maven("https://repo.papermc.io/repository/maven-public/")
    }
}

// build.gradle.kts
plugins {
    java
    id("com.gradleup.shadow") version "8.3.0"            // Fat JAR (shade)
    id("xyz.jpenilla.run-paper") version "2.3.1"          // Test server
    // If NMS is needed:
    // id("io.papermc.paperweight.userdev") version "2.0.0-beta.19"
}

group = "com.example"
version = "1.0.0"

repositories {
    mavenCentral()
    maven("https://repo.papermc.io/repository/maven-public/")
}

dependencies {
    // API only:
    compileOnly("io.papermc.paper:paper-api:1.21.4-R0.1-SNAPSHOT")
    // If NMS is needed, use instead of API:
    // paperweight.paperDevBundle("1.21.4-R0.1-SNAPSHOT")
}

java {
    toolchain.languageVersion.set(JavaLanguageVersion.of(21))
}

tasks.processResources {
    filteringCharset = "UTF-8"
    filesMatching("plugin.yml") {
        expand("version" to project.version)
    }
}

1.2 Maven

<repositories>
    <repository>
        <id>papermc</id>
        <url>https://repo.papermc.io/repository/maven-public/</url>
    </repository>
</repositories>
<dependencies>
    <dependency>
        <groupId>io.papermc.paper</groupId>
        <artifactId>paper-api</artifactId>
        <version>1.21.4-R0.1-SNAPSHOT</version>
        <scope>provided</scope>
    </dependency>
</dependencies>
<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.13.0</version>
            <configuration>
                <release>21</release>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>3.6.0</version>
        </plugin>
    </plugins>
</build>