Can anybody help me to solve the problem which is about the "super" in Java?

The "super" part I'm not very clear in Java, so how can I code it?

public class AggressiveAlien extends Alien
{

public AggressiveAlien(XYCoordination currentLocation, int energyCanister)
{
 super(currentLocation,开发者_如何学Go energyCanister);
}

public int collectCanister(NormalPlanet canister)
{
 super.collectCanister(canister);
 n=1;
}

private boolean attack(int lifePoints)
{
 boolean attack;
 if (AggresiveAlien.currentLocation() = Alien.getOtherAlien())
 {
  AggresiveAlien.energyCanisters = (int) (1/2) * Alien.energyCanisters + AggresiveAlien.energyCanisters;
  lifePoints = lifePoints - 1;
  attack = true;
 }
 return attack;
 }
}

What you have written is correct, provided that the Alien class has a constructor with the signature:

public Alien(XYCoordination, int)

Specifically,

super(currentLocation, energyCanister);

means, before you run this constructor run the constructor for the immediate superclass passing it the currentLocation and energyCanister values. Note that every constructor (apart for the Object constructor) chains to a superclass constructor, either explicitly or implicitly.

However, the following is probably incorrect:

AggresiveAlien.currentLocation()

That requires currentLocation() to be a static method, and that would imply that all instances of a AggresiveAlien have the same location ... which doesn't make a lot of sense. In fact, I think the method needs to be an instance method, and the call would therefore have to be:

this.currentLocation()

or just

currentLocation()

You have made this mistake in a number of places.

It means "call the version of this method (or constructor) that's defined in the immediate superclass".