Is my try-catch in the wrong place?

hmm.. So my line13 must be in try-catch brackets?

edit: I got it, I put in to try-block whole code from line 13 to line 33. Then to catch-block put this same code, but above, first line catch-block put "File don't exist."

try {
        String plikZrodlowyNazwa = reader.readLine();
        String plikDocelowyNazwa = reader.readLine();

        InputStream fileInputStream = getInputStream(plikZrodlowyNazwa);
        OutputStream fileOutputStream = getOutputStream(plikDocelowyNazwa);


            while (fileInputStream.available() > 0) {
                int dane = fileInputStream.read();
                fileOutputStream.write(dane);
            }
            fileInputStream.close();
            fileOutputStream.close();

        } catch (FileNotFoundException e) {
            System.out.println("Plik nie istnieje.");
            String plikZrodlowyNazwa = reader.readLine();
            String plikDocelowyNazwa = reader.readLine();
            InputStream fileInputStream = getInputStream(plikZrodlowyNazwa);
            OutputStream fileOutputStream = getOutputStream(plikDocelowyNazwa);


            while (fileInputStream.available() > 0) {
                int dane = fileInputStream.read();
                fileOutputStream.write(dane);
            }
            fileInputStream.close();
            fileOutputStream.close();

        }

With that translation, I mean, person CG who write this sentence in polish. For me, in polish is very bad write. And I don't have a view to original English text. So I am confused. Because there in my reasoning reading in Polish, writed, do: "File don't exist" load "name file" and then again, load "name file" What is the reason to load name file twice? Maybe what they meant was: "The file does not exist." and load the file name again and only then load the target file. So in Polish is like that: "Plik nie istnieje." i wczytać nazwę pliku jeszcze raz i dopiero wtedy wczytać nazwę pliku docelowegoy. (docelowy) "File don't exist" load "name file" and then again, load "file" Anyway, there is something messy 🤔 The whole sentence suggests that I am operating on the same source file. No... hmmm.... wczytac nazwę pliku docelowego = the name of the destination file. But there is a question, for what. They have in means, give the file a name under which it will be saved? Anyway, they can write this sentence better. What this code does. He wants / receive from user, name of file, and next want from user get new name file? Saving the same file but in different name? Is like re-name file. ?

1) You read a source file name in the program. But the user accidentally enters a wrong filename that doesn't exist (but the program doesn't know that yet.) 2) You call the getInputStream method in the program and send it this wrong= non-existent filename. The method cannot create a stream for a non-existent file, so it will throw an exception, back to main(). 3) Now the Exception is here in main(), in the try block where you called getInputStream(). The control moves on to the catch block. This block automatically catches this "File does not exist" exception. - In this catch block you should print "Sorry dear user, but no such file exists. Please give me a good filename now!":) ("Plik nie istnieje.") - In this catch-block you have to read a filename again, still the name of the source file. Assuming that the user will now finally provide a file name that actually exists and without errors, we now call the getInputStream() method without another try-catch block. BEFORE THIS POINT IT IS FORBIDDEN TO READ IN A DESTINATION-FILENAME OR TO CREATE AN OUTPUT-STREAM - just because the requirements now require this. After you have created the output stream, you will need this: while (fileInputStream.available() > 0) and read+write. - - - - - - - - - - - - I am copying a comment from a fellow student: Switch/Cypher Level 25 , Bexleyheath, United Kingdom 21 September 2020, 11:52 Lots of people tried to clarify this task, here's what I found useful: You ONLY read the output filename AFTER you've checked whether the INPUT one is valid. 1. Enter Input filename. 2. IF it's not valid, read another Input filename. 3. if that's not valid either, program ends with an exception. 4. If that one is valid or the first is valid THEN read the output filename.

So CG shouldn't pass my sentence, yet it did. After these explanations, I tried executing this code on files from the desktop. I corrected according to your instructions, and got this:

try {
String plikZrodlowyNazwa = reader.readLine();
InputStream fileInputStream = getInputStream(plikZrodlowyNazwa);

} catch (FileNotFoundException e) {
    System.out.println("Plik nie istnieje.");
    String plikZrodlowyNazwa = reader.readLine();
    String plikDocelowyNazwa = reader.readLine();
    InputStream fileInputStream = getInputStream(plikZrodlowyNazwa);
    OutputStream fileOutputStream = getOutputStream(plikDocelowyNazwa);

    while (fileInputStream.available() > 0) {
        int dane = fileInputStream.read();
        fileOutputStream.write(dane);
    }
    fileInputStream.close();
    fileOutputStream.close();
}

Console Output:

"C:\Program Files\Java\jdk1.8.0_251\bin\java.exe"
C:\Users\PC\Desktop\java1.txt
Plik nie istnieje.
C:\Users\PC\Desktop\java1.txt
C:\Users\PC\Desktop\java3.txt
Exception in thread "main" java.io.FileNotFoundException: C:\Users\PC\Desktop\java1.txt (Nie można odnaleźć określonego pliku)

But shouldn't the while loop be replaced by an if loop, so that the user enters, until he enters the correct name of the existing file? I once read about GOTO, if the condition is not met, the program went back to the desired line. Unhappily I can't retry to pass the task, I wonder if it would pass. So what do you think?

1) "But shouldn't the while loop be replaced by an if loop, so that the user enters until he enters the correct name of the existing file?" No, you shouldn't. If you want to write a program that you think is ideal, it should. But now you have to write the program that the requirements specify. And that's not what they're asking us to do. The requirement assumes that the second time the user will enter a CORRECT AND EXISTING FILENAME CERTAINLY. You tested your program with this source-filename: C:\Users\PC\Desktop\java1.txt And I see from the output of the program that this was a non-existent filename. So the program asks for a source file name a second time. But you typed the same non-existing filename again: C:\Users\PC\Desktop\java1.txt but the requirements and the way the program works implies that the second time not the same non-existent filename wil be inputted by the user! (Please read the original requirements carefully again.) 2) the catch block will only be executed if the first filename was incorrect and an Exception was thrown. This Exception must be caught, that's what the catch block is for. - But if the first filename input was already correct, then there is no Exception and the program never goes to the catch block. Therefore, you should not write so much code in the catch block, because in this case it will never be executed the followings: - creating the outputstream, - copying the contents of the file, - closing the streams. You need to write these outside/after the catch-block. 3) Please share your latest attempt to solve this task in a completely new help post, with sharing the latest program, because now it becomes untraceable and unclear what you changed in your program and what you didn't change and what the validator reacted to.

@3) Unfortunately I can't, Validator says the task is passed. 😬 I passed it with the code from the first answer. I can't create a new help post with the passed assignment attachment 😞. I'll add a link to the attachment. You will be able to see all the code it passed me with. (link) Just from our conversation, it seems that this is not the correct solution. But you probably can't validate again either. 😞 @2) I forgot, I didn't think of that. 😅 Ok, so this i my third code.

package pl.codegym.task.task09.task0929;

import java.io.*;

/*
Sprawmy, by kod robił coś pożytecznego!
*/

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        try {
        String plikZrodlowyNazwa = reader.readLine();
        InputStream fileInputStream = getInputStream(plikZrodlowyNazwa);

        } catch (FileNotFoundException e) {
            System.out.println("Plik nie istnieje.");
        }
        String plikZrodlowyNazwa = reader.readLine();
        InputStream fileInputStream = getInputStream(plikZrodlowyNazwa);

        String plikDocelowyNazwa = reader.readLine();
        OutputStream fileOutputStream = getOutputStream(plikDocelowyNazwa);

        while (fileInputStream.available() > 0) {
            int dane = fileInputStream.read();
            fileOutputStream.write(dane);
        }
        fileInputStream.close();
        fileOutputStream.close();

    }

    public static InputStream getInputStream(String nazwaPliku) throws IOException {
        return new FileInputStream(nazwaPliku);
    }

    public static OutputStream getOutputStream(String nazwaPliku) throws IOException {
        return new FileOutputStream(nazwaPliku);
    }
}

Great it is passed:) I can't verify with the validator again either. But I would think the solution would be right only if we would move the curly bracket from line 19 to line 22. At least that's how I solved it:)

✌😁 I tried something like this, but then I receive error. Cannot resolve symbol 'fileInputStream'. I think there is something wrong with validation in this task.

fileInputStream is declared in the try and in the catch block and has its scope only there, each in its own block. If you try to use it outside these blocks, you will get that cannot resolve symbol. You'd have to declare the variable outside try-catch, maybe right after the BufferedReader declaration (just a InputStream fileInputStream; eventually asign null). Later, inside the try block, you can initialize it. Then you have scope over the entire main. But the rest you're talking about... sorry, my attention span is not always the best 😒. I have to pass 🏳 Just ask me if you get stuck, brother Tuck 😜🤪

Yes, I was not too precise yesterday::

try {
        String plikZrodlowyNazwa = reader.readLine();
        InputStream fileInputStream = getInputStream(plikZrodlowyNazwa);
}
catch (FileNotFoundException e) {
            System.out.println("Plik nie istnieje.");
            String plikZrodlowyNazwa = reader.readLine();
            InputStream fileInputStream = getInputStream(plikZrodlowyNazwa);
}

Here the variable fileInputStream exists only inside the 'catch' block, so we cannot use it later. Whatever is declared inside a block exists only inside the block, and then ceases to exist. This would be correct:

InputStream fileInputStream;
try {
        String plikZrodlowyNazwa = reader.readLine();
        InputStream fileInputStream = getInputStream(plikZrodlowyNazwa);
}
catch (FileNotFoundException e) {
            System.out.println("Plik nie istnieje.");
            String plikZrodlowyNazwa = reader.readLine();
            fileInputStream = getInputStream(plikZrodlowyNazwa);
}

So, better is initialize empty object "InputStream fileInputStream;" above try-catch block. There is no need, to initialize twice, in try-block and catch-block. There only declare contents "fileInputStrem" to get connection from inside to outside. If I initialize inside object try-catch, I don't have connection with code outside bracket. What's happen with that object, when I do initialize it twice or three, in outside and inside try and catch block? First be alive all the time, and the rest inside try-catch will be dead and don't leave any data? Or the object, it will be overwritten by try-catch? After all will be dead/removed?

I think, I have to explain the meaning of the words "initialize" and "declare" to you, I think that's what's missing to compile the whole thing. 1) to declare:

int x;

// we declared a variable 'x' which type is int. It does not have a value yet! In other words, it is not initialized yet.

Cat cat1;

// we declared a variable cat1, with type Cat. But no Cat object has been assigned yet! In other words, not yet initialized. So this is not an empty object. Because there is no Cat object yet! It's just an "empty" variable, which we know that we can store only Cat-objects in it in the future.

FileInputStream fis;

// I declared a variable named fis, whose type is FileInputStream. There is no FileInputStream object assigned yet! In other words, this variable is not initialized yet. It is not an empty object. No FileInputStream object exists yet! It's just an "empty" variable that we know we can store only FileInputStream objects in it in the future. Declare: I tell the Java Virtual Machine (JVM) that: - I will use a variable with a certain name, - and what type of data we can put into this variable later. 2) to initialize: x=2; // give the previously created empty variable x the value 2.

cat1=new Cat();

// assign a new Cat object to the previously created empty variable cat1.

fis = new FileInputStream("C:\Users\PC\Desktop\java1.txt");

// assign a new FileInputStream object to the previously created empty variable fis. To initialize: when you assign the first value to a variable that was previously empty and never contained any value before. 3) declaration and initialisation in one step: int y = 5; FileInputStream fis2 = new FileInputStream("C:\test.txt");

So you cannot initialize twice or three times. It can only be done once. Then, of course, you can give the variable another value again later, however many times, but that is not called initialization. Variable lifetime: the variable is only available within the code block where it is declared. Not where it was initialized! Yesterday I wrote wrong code again (I didn't test it...) So this code is wrong:

InputStream fileInputStream;
try {
        String plikZrodlowyNazwa = reader.readLine();
        InputStream fileInputStream = getInputStream(plikZrodlowyNazwa);
}
catch (FileNotFoundException e) {
        System.out.println("Plik nie istnieje.");
        String plikZrodlowyNazwa = reader.readLine();
        fileInputStream = getInputStream(plikZrodlowyNazwa);
}

I tested it today and the JVM thows an error: Line 4: "error: variable fileInputStream is already defined in method main" = so I cannot declare the same variable twice. But that's really good, I tested it:

InputStream fileInputStream;
try {
        String plikZrodlowyNazwa = reader.readLine();
        fileInputStream = getInputStream(plikZrodlowyNazwa);
}
catch (FileNotFoundException e) {
        System.out.println("Plik nie istnieje.");
        String plikZrodlowyNazwa = reader.readLine();
        fileInputStream = getInputStream(plikZrodlowyNazwa);
}

The code you share:

try {
    String plikZrodlowyNazwa = reader.readLine();
    InputStream fileInputStream = getInputStream(plikZrodlowyNazwa);
}
catch (FileNotFoundException e) {
    System.out.println("Plik nie istnieje.");
}
    String plikZrodlowyNazwa = reader.readLine();
    InputStream fileInputStream = getInputStream(plikZrodlowyNazwa);

The variable fileInputStream declared in line 3 can only be used within the try block. It exists only within the block. This would be a problem, if this variable were needed later (if it were not a requirement of the task to throw an exception for an incorrect filename, and to read in a new filename.) You can declare a variable called fileInputStream again in line 9 because the variable of the same name declared in line 3 no longer exists here.

This is called variable shadowing... just so you know the child has a name. What you do with this information, my dear friend, is in the stars... isn't that really crazy, crazy 😜🤪 But go on ignoring me. I will continue anyway and throw a little info into the room every now and then. 🤓 tee-hee, tada 🧐🤡

Thank you for catching me out and setting me straight. Sometimes I can misunderstand, name and duplicate something. 😅 Lisa I never meant to ignore you. I really, really did. 🤗 You help me a lot too.

You're soooo cute 😌🤗😊