Change Vanilla Fluid Collision Block Result

Main topics in this chapter: ForgeEvents and Forge's BlockEvent.FluidPlaceBlockEvent. All code in this chapter belongs in startup_scripts.

Full Code

let $BlockEvent = Java.loadClass("net.minecraftforge.event.level.BlockEvent")

ForgeEvents.onEvent($BlockEvent.FluidPlaceBlockEvent,event=>{
    let block = event.getNewState().getBlock();
    if (block.id == "minecraft:stone"){
        event.setNewState(Block.getBlock('minecraft:netherrack').defaultBlockState());
    }
})

The code above changes the result of lava-water collision from stone to netherrack.