I would like to set a world static. In bukkit I use this method
private static void setWorldStatic(World world, boolean static_boolean) throws Exception
{
Field static_field = World.class.getDeclaredField(“isClientSide”);
static_field.setAccessible(true);
static_field.set(world, Boolean.valueOf(static_boolean));
}
But I don’t find how on sponge 
What are you hoping to accomplish with this method? The reflection does in no way enforce you to use a static method, an instance method could do exactly the same.
Honestly it looks like a code smell; probably what you are trying to accomplish can be done differently.
I would like to make the world static for prevent the update of the block. I would like to pose a sign on a wall. break the wall and the sign don’t fall for example
Then you need to work with events, as explained here (as you should have on Bukkit).
You might be interested in block related events, specifically the NotifyNeighborBlockEvent which, I think, could be used to prevent the sign break you mentioned.
Do you have a example please. Because I’m new on sponge.
Drop this method into your plugin somewhere (you can name it whatever you want):
@Listener
public void onBlockChange(ChangeBlockEvent e) {
if (/* check if you want to cancel the change */) {
e.setCancelled(true);
}
}
Also, if it’s not in your main plugin class (the one with @Plugin), you’ll need to create a new instance of whatever class you put the method in and register it with Sponge.getEventManager().
Sorry but I find. Thanks