Introduction: Why Start with Minecraft?

Minecraft is one of the best games to begin your modding journey. Its Java-based architecture, a massive modding community, and the well-documented Minecraft Forge framework make it accessible even if you've never written a line of game code. By the end of this tutorial, you'll have a working mod that adds a custom item to the game.

What You'll Need

  • Java Development Kit (JDK) 17 — Download from Adoptium or Oracle
  • IntelliJ IDEA (Community Edition is free) or Eclipse
  • Minecraft Forge MDK — The Mod Development Kit, available at files.minecraftforge.net
  • A copy of Minecraft Java Edition
  • Basic familiarity with Java syntax (variables, classes, methods)

Step 1: Set Up Your Development Environment

  1. Install JDK 17 and verify it's working by running java -version in your terminal.
  2. Download the Forge MDK for your target Minecraft version and extract it to a new folder.
  3. Open a terminal in that folder and run:
    ./gradlew genIntellijRuns (Mac/Linux) or gradlew genIntellijRuns (Windows)
  4. Open IntelliJ IDEA, choose Open Project, and select the folder. Let it index and download dependencies — this takes a few minutes.

Step 2: Understand the Project Structure

Inside the MDK you'll find these key directories:

  • src/main/java/ — Your Java source files live here
  • src/main/resources/ — Textures, models, and data files
  • build.gradle — Your mod's build configuration

Open build.gradle and update the group, archivesBaseName, and version fields with your mod's identity. Then open your main mod class (inside the java folder) and set your mod's ID.

Step 3: Register a Custom Item

Create a new Java class called ModItems.java in your mod's package. Here's a minimal example:

public class ModItems {
    public static final DeferredRegister<Item> ITEMS =
        DeferredRegister.create(ForgeRegistries.ITEMS, "yourmodid");

    public static final RegistryObject<Item> MY_ITEM =
        ITEMS.register("my_item",
            () -> new Item(new Item.Properties()));
}

Then in your main mod class, add the following to the constructor:

ModItems.ITEMS.register(modEventBus);

Step 4: Add a Texture and Model

  1. Create a 16x16 PNG image for your item and save it to:
    src/main/resources/assets/yourmodid/textures/item/my_item.png
  2. Create a model JSON file at:
    src/main/resources/assets/yourmodid/models/item/my_item.json
  3. The model file should reference your texture using the standard item model parent format.

Step 5: Test Your Mod In-Game

In IntelliJ, run the runClient Gradle task. Minecraft will launch with your mod loaded. Open creative mode, search for your item's ID in the item list, and you should see it appear with your texture.

Common Beginner Mistakes

  • Mismatched mod IDs — Make sure the ID in your Java code, JSON files, and build.gradle all match exactly.
  • Wrong JDK version — Different Forge versions require specific JDK versions. Always check the Forge documentation.
  • Forgetting to register — Any new game object (item, block, entity) must be registered using Forge's Deferred Register system.

Where to Go Next

Once you've added a custom item, the modding world opens up. From here you can add custom blocks, crafting recipes, entities, and eventually entirely new dimensions. The official Forge documentation and communities like MinecraftForge Discord and CurseForge forums are invaluable as you progress.