Paper/src/main/java/net/minecraft/server/BlockStationary.java

package net.minecraft.server;

// CraftBukkit start
import org.bukkit.Server;
import org.bukkit.entity.Player;
import org.bukkit.event.block.BlockIgniteEvent;
import org.bukkit.event.block.BlockIgniteEvent.IgniteCause;
import org.bukkit.craftbukkit.CraftWorld;
import java.util.Random;
// CraftBukkit end

public class BlockStationary extends BlockFluids {

    protected BlockStationary(int k, Material material) {
        super(k, material);
        a(false);
        if (material == Material.g) {
            a(true);
        }
    }

    public void b(World world, int k, int l, int i1, int j1) {
        super.b(world, k, l, i1, j1);
        if (world.a(k, l, i1) == bi) {
            i(world, k, l, i1);
        }
    }

    private void i(World world, int k, int l, int i1) {
        int j1 = world.b(k, l, i1);

        world.i = true;
        world.a(k, l, i1, bi - 1, j1);
        world.b(k, l, i1, k, l, i1);
        world.i(k, l, i1, bi - 1);
        world.i = false;
    }

    public void a(World world, int k, int l, int i1, Random random) {
        if (bt == Material.g) {
            int j1 = random.nextInt(3);

            for (int k1 = 0; k1 < j1; k1++) {
                k += random.nextInt(3) - 1;
                l++;
                i1 += random.nextInt(3) - 1;
                int l1 = world.a(k, l, i1);

                if (l1 == 0) {
                    // this checks if an adjacent block is flammable before lighting this block.
                    // perhaps we can reduce spam by checking this earlier.
                    if (j(world, k - 1, l, i1) || j(world, k + 1, l, i1) || j(world, k, l, i1 - 1) || j(world, k, l, i1 + 1) || j(world, k, l - 1, i1) || j(world, k, l + 1, i1)) {
                        // CraftBukkit start: prevent lava putting something on fire.
                        Server server = ((WorldServer)world).getServer();
                        CraftWorld cworld = ((WorldServer)world).getWorld();
                        
                        org.bukkit.block.Block theBlock = cworld.getBlockAt(k, l, i1);
                        IgniteCause igniteCause = BlockIgniteEvent.IgniteCause.LAVA;
                        Player thePlayer = null;
                        
                        if (theBlock.getTypeId() != Block.ar.bi){
                            BlockIgniteEvent event = new BlockIgniteEvent(theBlock, igniteCause, thePlayer);
                            server.getPluginManager().callEvent(event);
                            if (event.isCancelled()) {
                                continue;
                            }
                        }
                        // CraftBukkit end
                        world.e(k, l, i1, Block.ar.bi);
                        return;
                    }
                    continue;
                }
                if (Block.m[l1].bt.c()) {
                    return;
                }
            }
        }
    }

    private boolean j(World world, int k, int l, int i1) {
        return world.c(k, l, i1).e();
    }
}