Code freezing server during world load, really cannot understand why

[Mad Alchemist]

I have added an option to replace all skeletons in overworld with zombies, but it may (exactly, MAY and not WILL) crash server during world load.
Here is a problemmatic piece of code:
 

/* This code is inside EntityJoinWorldEvent event handler */
/* Replace skeletons with zombies? */


        if (ConfigHandler.GENERAL.noSkeletons.get()) {
                //Zombienation.LOGGER.debug("Attempting to replace skeleton with zombie...");
                if (event.getEntity() instanceof SkeletonEntity || event.getEntity() instanceof StrayEntity) {
                    if (event.getEntity().level.dimension().location().toString().equals("minecraft:overworld")) {
                        /* Random zombie randomly turns into any other zombie from vanilla or my mod on spawn */
                        /* Zombie itself isn't a problem - I have tried vanilla zombies or even pigs */
                        RandomZombie zombie = new RandomZombie(ZombiesRegistry.RANDOM_ZOMBIE.get(), event.getEntity().level);
                        zombie.setPos(event.getEntity().getX(), event.getEntity().getY(), event.getEntity().getZ());
                        event.getEntity().level.addFreshEntity(zombie); //Server freezes at this line
                        /* Line below is never reached if server freezes, so it can't be an issue? */
                        event.setCanceled(true);
                        //Zombienation.LOGGER.debug("Done!");
                    }
                }
        }

 

Edited April 23, 2022 by Mad Alchemist
Fixed a typo in code piece

[Mad Alchemist]

23 hours ago, diesieben07 said:

This should really check the entity type instead, not the class.

Leaving it "as is", it will also replace everything that extends SkeletonEntity or StrayEntity classes?
Not sure if I want it... It may be desired behavior if some mod adds skeletons by extending vanilla ones...

And thanks for help, I probably would never find out it myself...

 

[Mad Alchemist]

Quote

Look at ForgeInternalHandler#onEntityJoinWorld for how to do it properly.

Where is this "ForgeInternalHandler" located? And, can't I just do it in entity tick and check if chunk entity is in is fully loaded?