How Exception will be thrown from orElseThrow method in JAVA 8?

I have one field called isExist and it is either false or true in line #1.
based on this, in line#2 either Optional.empty() is executed or Optional.of(1) is getting executed but never Exception is thrown from orElseThrow method in line#2.

can anyone please explain when Exception will be thrown ? on which condition Exception will be thrown ?

line#1 final boolean isExist  = (user != null && CollectionUtils.isNotEmpty(user.getIds())
                && user.getIds().contains(id));

line#2 (isExist ? Optional.empty() : Optional.of(1)).orElseThrow(
                () -> new Exception());

>Solution :

From line1, it will assign true/false to isExist variable.

So we have 2 possibility here.

isExist = true or isExist = false;

At line 2, the tertiary condition can be understand as:

Optional optional = null;
if(isExist){
   optional = Optional.empty();
}else{
   optional = Optional.of(1)
}
optional.orElseThrow(() -> new Exception());

orElseThrow only throw exception when optional variable is empty, it mean when isExist = true. If isExist = false, nothing happen.
You can see below signature to understand the basic concept of orElseThrow …

public void orElseThrow(Exception ex){
  if(!isPresent()){
     throw ex;
  }
}