Extending BlockEntity for Custom Data

Custom data storage (for blocks) is extremely simple using the BlockEntity class.

Extending BlockEntity and Adding Some Properties

public class MyBlockEntity extends BlockEntity {
    public Property<Integer> myInt = new Property<>(Codecs.INT, 0);
    
    public MyBlockEntity(CustomBlock block) {
        super(block);
    }
}

However the entity is useless right now, you need to add it to a Custom Block as follows:

public class MyBlock extends CustomBlock {
    public MyBlock(Identifier id) {
        super(id, Material.GRASS_BLOCK);
    }
    
    @Override
    public MyBlockEntity createBlockEntity(Location lco) {
        return new MyBlockEntity(this);
    }
    
    // So that you dont have to cast everytime
    @Override
    public MyBlockEntity getEntity() {
        return (MyBlockEntity) super();
    }
}

Now the block MyBlock will use MyBlockEntity and so the property will be accessible (block.getEntity().myInt.get())

BlockEntity also has the following hooks that you may override:

BlockEntity#onLoad
BlockEntity#onSave
BlockEntity#serverTick
BlockEntity#randomTick

15 December 2025