#1 Basic Java call:
import:
    java.lang.System

set {_nl} to System.lineSeparator()

#2 Event listening
import:
    org.bukkit.event.block.CauldronLevelChangeEvent

on CauldronLevelChangeEvent:
    broadcast "The cauldron at %event.getBlock().getLocation()% had its level changed from %event.getOldLevel()% to %event.getNewLevel()%"

#3 Custom syntax
effect send (experience|xp) change of %number% [with level %-number%] to %players%:
    trigger:
        set {_progress} to expr-1
        set {_level} to expr-2
        loop exprs-3:
            set {_p} to loop-value
            if {_level} is set:
                {_p}.sendExperienceChange({_progress}, {_level})
            else:
                {_p}.sendExperienceChange({_progress})

send xp change of 0.75 with level 9 to player