if(player.getLocation().getWorld() == world){

Its doesnt work. What is the normal world name. (Its world, but its doesnt work)

 

Don't use ==
That's for integers
You have to use a string

 

oran10majar The == method only works properly for primitive objects- int, float, double, char, etc.

To compare objects, such as Worlds, you need to use the .equals() method.

In this case:

if (player.getLocation().getWorld().equals(world))

 

Moved to correct section.

 

I didnt understand the code, it doesnt work for me

 

To check the world name is "world", use:
if (player.getLocation().getWorld().getName().equals("world"))


Someguyfromcrowd == compares if two objects are the same object (instead of checking if their contents are the equals using .equals()), not just for primitive data types

 

Chinwe not quite correct. You need to be more precise on what == does.

The term "same object" can be misinterpreted since new String("Hello") == new String("Hello") seem to be the same object but this will return false if checked.

This is because it compares for the object reference and not its values.

To be more precise: If == is used to compare two objects then it compares the object reference and not the values.

So whenever you compare a value use equals.

(Slightly offtopic)

I also recommend using itemStack.getType().equals(Material.AIR) instead of getType() == Material.AIR since the first one is more fluid and better readable.

You could use the latter since that is what equals would do for enums but as said its confusing to read == for many devs therefore should be avoided.