import cn.nukkit.level.particle.CriticalParticle; //导入依赖的package包/类
@Override
public boolean onUpdate(int currentTick) {
    if (this.closed) {
        return false;
    }

    this.timing.startTiming();

    boolean hasUpdate = super.onUpdate(currentTick);

    if (!this.hadCollision && this.isCritical) {
        NukkitRandom random = new NukkitRandom();
        this.level.addParticle(new CriticalParticle(this.add(
                this.getWidth() / 2 + ((double) NukkitMath.randomRange(random, -100, 100)) / 500,
                this.getHeight() / 2 + ((double) NukkitMath.randomRange(random, -100, 100)) / 500,
                this.getWidth() / 2 + ((double) NukkitMath.randomRange(random, -100, 100)) / 500)));
    } else if (this.onGround) {
        this.isCritical = false;
    }

    if (this.age > 1200) {
        this.kill();
        hasUpdate = true;
    }

    this.timing.stopTiming();

    return hasUpdate;
}
 

import cn.nukkit.level.particle.CriticalParticle; //导入依赖的package包/类
@Override
public boolean attack(EntityDamageEvent source) {
    if (!this.isAlive()) {
        return false;
    }

    if (this.isCreative()
            && source.getCause() != DamageCause.MAGIC
            && source.getCause() != DamageCause.SUICIDE
            && source.getCause() != DamageCause.VOID
            ) {
            //source.setCancelled();
            return false;
    } else if (this.getAdventureSettings().get(Type.ALLOW_FLIGHT) && source.getCause() == DamageCause.FALL) {
            //source.setCancelled();
            return false;
    } else if (source.getCause() == DamageCause.FALL) {
        if (this.getLevel().getBlock(this.getPosition().floor().add(0.5, -1, 0.5)).getId() == Block.SLIME_BLOCK) {
            if (!this.isSneaking()) {
                //source.setCancelled();
                return false;
            }
        }
    }

    if (source instanceof EntityDamageByEntityEvent) {
        Entity damager = ((EntityDamageByEntityEvent) source).getDamager();
        if (damager instanceof Player) {
            ((Player) damager).getFoodData().updateFoodExpLevel(0.3);
        }

        if (!damager.onGround) {
            NukkitRandom random = new NukkitRandom();
            for (int i = 0; i < 5; i++) {
                CriticalParticle par = new CriticalParticle(new Vector3(this.x + random.nextRange(-15, 15) / 10, this.y + random.nextRange(0, 20) / 10, this.z + random.nextRange(-15, 15) / 10));
                this.getLevel().addParticle(par);
            }

            source.setDamage((float) (source.getDamage() * 1.5));
        }
    }

    if (super.attack(source)) { //!source.isCancelled()
        if (this.getLastDamageCause() == source && this.spawned) {
            this.getFoodData().updateFoodExpLevel(0.3);
            EntityEventPacket pk = new EntityEventPacket();
            pk.entityRuntimeId = this.id;
            pk.event = EntityEventPacket.HURT_ANIMATION;
            this.dataPacket(pk);
        }
        return true;

    } else {
        return false;
    }
}