with skript-reflect:

Code (Text):

1. import:
2.   org.bukkit.event.entity.EntityAirChangeEvent
3. on EntityAirChangeEvent:
4.   broadcast "%event.getAmount()%" # current amount of air
5.   broadcast "%event.setAmount(100)%" # Sets the amount of air remaining for the entity (measured in ticks.)
6.   broadcast "%event.getEntity()%" # what entity called event

 

Let's basics, in my code I imported some class - org.bukkit.event.entity.EntityAirChangeEvent
Reflect allows us using 'on EntityAirChangeEvent' if class what we are using is Bukkit event. This class is Bukkit event because inherited from org.bukkit.event.Event
spigot docs link



Lets go deeper:
This event has many functions inside named 'methods'

Its like skript functions, but with java types. Reflect allow use Skript types as java types (auto convert)
For example:
method .setAmount(int amount) can be used as:

Code (Text):

1. import:
2.   org.bukkit.event.entity.EntityAirChangeEvent
3. on EntityAirChangeEvent:
4.   event.setAmount(5)

Class EntityAirChangeEvent also have methods inherited from parent classes:

In our case we need exclude all entities but player
Lets check what doing method .getEntityType()


Its return EntityType, so we need get EntityType object for our compare, lets check what is EntityType:

Enum is something like constant values, like list with text index in Skript but cant be changed.
For example EntityType.BAT return BAT type , but we need player, lets find: CTRL+F -> player

Okey, we can get EntityType.PLAYER, we have needed event, we have method to get EntityType of entity in event:

Code (Text):

1. import:
2.   org.bukkit.event.entity.EntityAirChangeEvent
3.   org.bukkit.entity.EntityType
4. on EntityAirChangeEvent:
5.   if event.getEntityType() is EntityType.PLAYER:
6.     set {_player} to event.getEntity()
7.     broadcast "Its player: %{_player}%!!!"