How to return a string from an array of characters

[neon mural]

Hello guys, consider this question:

Which of the following is the correct statement to return a string from an array a of characters?
Select one:
A. New String(a)
B. toString(a)
C. convertToString(a)
D. String.toString(a)

Can someone explain which answer is correct, why and why the others are incorrect please; according to chatgpt, the answer is a but I don't understand why... also I don't have the correct answer so I don't know if chatgpt is correct.

Thanks in advance

[quiet walrus]

<@&987246399047479336> please have a look, thanks.

Here is an AI assisted attempt to answer your question 🤖. Maybe it helps! In any case, a human is on the way 👍. To continue talking to the AI, you can use </chatgpt:1108714622413963314>.

A. String str = new String(a);

[primal tangle]

A is correct, if you write new instead of New

[kind vigil]

Is this a test?

[neon mural]

no practise questions

[kind vigil]

Then what do you think?

Why any of them would be correct or wrong And why?

[primal tangle]

In my opinion this is a horrible practice question, it doesn't test your programming ability at all - only your memory.

[neon mural]

hmmm I would choose between A or B... A is creating a new object of type String and passing as arguments the array of characters... B is converting the array of characters into a string

[neon mural]

Yeah I agree 😭

[kind vigil]

But one exists while the other dont

[primal tangle]

I know from experience that new String(char[]) exists so I immediately knew A is the answer. All the other options do make sense, but it's just a matter of checking what's correct and what isn't.

[neon mural]

The problem is I don't know if the methods given actually exist, in my opinion, all of them is doing the same thing

[kind vigil]

Actually you can easily get rid of b and c since they would be impossible in java, if you know java, you know that they are wrong

[kind vigil]

Then learn which one exist, check the doc

[primal tangle]

"If you know java" is the key. For people who don't have enough experience, all choices make sense design-wise.

[neon mural]

I know that option B is used to convert an object into a string

[kind vigil]

Then it test your programming skills, what is the problem?

[neon mural]

Ok, will read some documentation then, thanks guys, really appreciate 👍

[kind vigil]

No, B is impossible

B and c are not valid java

[neon mural]

if B is incorrect so D also since it uses the toString method, right ?

[kind vigil]

B and c

You can't have a function in nothingness in java

You must put it in a class

[kind vigil]

D is valid java so it's possible

It's just... that java doesn't have such method

[neon mural]

yeah I see, thanks !!

[neon mural]

one last question.... can we say that we can easily get rid of B and C because here, we are considering an object of type String, so whenever we need to access an instance variable/instance method, we should write something like that: Object.method() [that's why D is correct java]

[primal tangle]

You are correct, let me explain 🙂
When you call a method, Java searches it in 2 places:

public class User
{
    public void sayHi()
    {
        //1. in the class itself
        say("Hi!");
    }

    public void printSelf()
    {
        //2. in the Object class, which every class inherits
        System.out.println(toString());
    }

    private void say(String message)
    {
        System.out.println("Message > " + message);
    }
}

If the method was not defined in these places - the code cannot be compiled.
We can safely ignore choices B and C because the Object class doesn't offer either.

[quiet walrus]

Detected code, here are some useful tools:

Formatted code

public class User {
  public void sayHi() {
    //1. in the class itself
    say("Hi!");
  }
  public void printSelf() {
    //2. in the Object class, which every class inherits
    System.out.println(toString());
  }
  private void say(String message) {
    System.out.println("Message > " + message);
  }
}

[neon mural]

Yep I see, thanks !!

[primal tangle]

I edited the first sentence, it was incorrect.

You're welcome 🙂

[neon mural]

By the way, how do we do to copy and paste a code from our IDE in discord? I mean like you have done above, it keeps the colour etc

[primal tangle]

Discord supports auto formatting for many languages

[neon mural]

oh okay didn't know how to do that, thanks once more !!