Java: returning a string from a method

Question

I'd like to point out that I'm very new to Java, which is why I may be making stupid mistakes.

I have a class called "Characters", which consists of 4 variables and multiple methods. All variables are private, so from what I've read, I need to use methods to do anything to them.

One of the methods is supposed to return one of the variables in string form, however I keep getting an error from both eclipse and when I run it. "This method must return a result of type "String". The error occurs on the first line of the method:

public String displayStats(String option) {
    switch (option) {
    case "charName":
        System.out.println(charName);
        return charName;
    case "charHealth":
        System.out.println(charHealth);
        String charHealth2 = Integer.toString(charHealth);
        return charHealth2;
    case "charMana":
        System.out.println(charMana);
        String charMana2 = Integer.toString(charMana);
        return charMana2;
    case "charStamina":
        System.out.println(charStamina);
        String charStamina2 = Integer.toString(charStamina);
        return charStamina2;
    default:
        System.out.println("Error on default");}
}

}

The full class:

package basics;

public class Characters {

    private String charName = "";
    private int charHealth = 0;
    private int charMana = 0;
    private int charStamina = 0;

    public void summoner(Characters player) {
        player.charName = "Summoner";
        player.charHealth = 80;
        player.charMana = 150;
        player.charStamina = 50;}

    public void sentinel(Characters player) {   
        player.charName = "Sentinel";
        player.charHealth = 200;
        player.charMana = 50;
        player.charStamina = 100;}

    public void beserker(Characters player) {
        player.charName = "Beserker";
        player.charHealth = 100;
        player.charMana = 0;
        player.charStamina = 200;}

    public void mage(Characters player) {
        player.charName = "Mage";
        player.charHealth = 80;
        player.charMana = 200;
        player.charStamina = 20;}   

    public String displayStats(String option) {
        switch (option) {
        case "charName":
            System.out.println(charName);
            return charName;
        case "charHealth":
            System.out.println(charHealth);
            String charHealth2 = Integer.toString(charHealth);
            return charHealth2;
        case "charMana":
            System.out.println(charMana);
            String charMana2 = Integer.toString(charMana);
            return charMana2;
        case "charStamina":
            System.out.println(charStamina);
            String charStamina2 = Integer.toString(charStamina);
            return charStamina2;
        default:
            System.out.println("Error on default");}
    }

}

What do you think will be returned to the caller if it hits that default case? — Jon Skeet
– Jon Skeet, Commented Feb 9, 2016 at 18:09
Normally you would break from each case statement, and have a single return from your method at the end. Multiple returns from a single method is considered bad practice, as it makes the code harder to follow — Kevin Hooke
– Kevin Hooke, Commented Feb 9, 2016 at 18:11
I think I may have focused too much on the declaration of the method. Thank you. — BaphOfWonder
– BaphOfWonder, Commented Feb 9, 2016 at 18:12
How does this even compile when all paths don't return a value in the method? Maybe you should check you compiler error/warning settings. — Tapani
– Tapani, Commented Feb 9, 2016 at 18:22

Mage Xy · Accepted Answer · 2016-02-09 18:12:29Z

1

You aren't returning anything in the default case of your switch statement, which means that there is a possibility (however small) that the method won't know what to return.

answered Feb 9, 2016 at 18:12

Mage Xy

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Comments

Idos · Accepted Answer · 2016-02-09 18:12:48Z

0

In the displayStats function you don't return a String in all paths of your code.
This is because the default doesn't return at all.

Maybe you wanted to write:

default:
    return "Error on default";

answered Feb 9, 2016 at 18:12

Idos

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Comments

TangledUpInBlue · Accepted Answer · 2016-02-09 18:13:44Z

0

Two problems: charName is a string, but charHealth, charMana, and charStamina are ints. Thus, your displayStats function isn't always returning a string.

Also, your default option in your switch statement should return a string as well.

It would be better to create an accessor function for each variable:

public String getCharName() {
    return charName;
}

public int getCharHealth() {
    return charHealth;
}

etc.

answered Feb 9, 2016 at 18:13

TangledUpInBlue

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Comments

John Morris · Accepted Answer · 2016-02-09 18:17:19Z

0

The method displayStats must always return a String or throw an exception. Since the code implies that the default case is an error, then throw an exception. At this point rather than create a new class of exception, just throw an IllegalArgumentException -- new IllegalArgumentException(option). When printed out it will state the type of exception and the value of the invalid option.

answered Feb 9, 2016 at 18:17

John Morris

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