为什么我的数组索引0出现stackoverflow错误

Question

This is my warrior class. I wanted to have an array of warriors in this class. The idea is to be able to call a method like this --> warrior.select(1) where it would get the warrior created at index 1. Hope that makes sense. Please explain to me why this error is happening.

Exception in thread "main" java.lang.StackOverflowError
    at pking.Warrior.<init>(Warrior.java:42)

Code

package pking;

public class Warrior {

    private String name;
    private int age;
    private String call;
    private int attackPower;
    private String weapon;

    public Warrior(String myName, int myAge, String myCall, int myAttackPower) {
        name = myName;
        age = myAge;
        call = myCall;
        attackPower = myAttackPower;
        weapon = "";
        Warrior[] warriors = new Warrior[4];
        warriors[0] = new Warrior("Spartacus", 40, "I AM SPARTACUS!", 9000);
        warriors[1] = new Warrior("Crixus", 35, "CHAMPION OF CAPUA", 8000);
        warriors[2] = new Warrior("Gannicus", 30, "SLAYER", 8000);
        warriors[3] = new Warrior("Alexander", 21, "I AM ALEXANDER, THE CODER", 0);
    }

    //Prints warriors name
    public void name() {
        System.out.println(name);
    }

    //Prints warriors age
    public void age() {
        System.out.println(age);
    }

    //Prints warriors call
    public void warriorsCall() {
        System.out.println(call);
    }

    //Prints warriors attack power
    public void attackPower() {
        System.out.println(attackPower);
    }

    //Equips warriors weapon and prints message
    public void equip(String myWeapon) {
        weapon = myWeapon;
        System.out.println("Equiped the: " + weapon);
    }

    //Prints warriors weapon
    public void weapon() {
        System.out.println(weapon);
    }

}

Answer 1

Your constructor is running an infinite loop as you are calling it recursively. Check these lines in your constructor :

    Warrior[] warriors = new Warrior[4];
    warriors[0] = new Warrior("Spartacus", 40, "I AM SPARTACUS!", 9000);
    warriors[1] = new Warrior("Crixus", 35, "CHAMPION OF CAPUA", 8000);
    warriors[2] = new Warrior("Gannicus", 30, "SLAYER OF VAGINAS", 8000);
    warriors[3] = new Warrior("Alexander", 21, "I AM ALEXANDER, THE CODER", 0);

for each Warrior array item instantiation you call the same constructor, which again try to create the array and initialise items, this keeps going on until stack overflows.

A better design strategy would be to create a new class, say Legion , which will contain a collection of Warrior s:

public class Legion {
    Warrior[] warriors;

    public Legion() {
        warriors = new Warrior[4];
        warriors[0] = new Warrior("Spartacus", 40, "I AM SPARTACUS!", 9000);
        warriors[1] = new Warrior("Crixus", 35, "CHAMPION OF CAPUA", 8000);
        warriors[2] = new Warrior("Gannicus", 30, "SLAYER OF VAGINAS", 8000);
        warriors[3] = new Warrior("Alexander", 21, "I AM ALEXANDER, THE CODER", 0);
    }

    // getters and setters
}

Answer 2

I am not going to repeat the reason for the StackOverflow exception, as that has already been answered (recursion problem in your constructor).

But, I think that what you probably wanted was to create those 4 special warriors once and not for every instance of a Warrior . And maybe you wanted to have them as constants somehow.

So maybe something like this:

public class Warrior {

    private static final List<Warrior> MEGA_WARRIORS =
        Collections.unmodifiableList(Arrays.asList(
            new Warrior("Spartacus", 40, "I AM SPARTACUS!", 9000),
            new Warrior("Crixus", 35, "CHAMPION OF CAPUA", 8000),
            new Warrior("Gannicus", 30, "SLAYER OF *censored*", 8000),
            new Warrior("Alexander", 21, "I AM ALEXANDER, THE CODER", 0)
        ));

    public static List<Warrior> getMegaWarriors() {
        return MEGA_WARRIORS;
    }

    private String name;
    private int age;
    private String call;
    private int attackPower;
    private String weapon;

    public Warrior(String myName, int myAge, String myCall, int myAttackPower) {
        name = myName;
        age = myAge;
        call = myCall;
        attackPower = myAttackPower;
        weapon = "";
    }

    //Prints warriors name
    public void name() {
        System.out.println(name);
    }

    //Prints warriors age
    public void age() {
        System.out.println(age);
    }

    //Prints warriors call
    public void warriorsCall() {
        System.out.println(call);
    }

    //Prints warriors attack power
    public void attackPower() {
        System.out.println(attackPower);
    }

    //Equips warriors weapon and prints message
    public void equip(String myWeapon) {
        weapon = myWeapon;
        System.out.println("Equiped the: " + weapon);
    }

    //Prints warriors weapon
    public void weapon() {
        System.out.println(weapon);
    }

}