这个 try catch 代码（Java）有什么问题？

Question

Been 2 hours I'm trying to compile my code, doesn't seem to work... Check out which line gives me a msg in the code has a comment.

Does the Try and catch isolate the scoop of a variable?

import java.io.*;
public class Tp3Partie2 {

    public static void main (String[] params) {
        int cmd;
        FileReader fEntree;
        FileReader fEntree2;
        BufferedReader entree;
        Cars [] tableau;
        try {
            fEntree = new FileReader( "test.txt" );
            fEntree2 = new FileReader( "test.txt" );
            LineNumberReader nbrLigne = new LineNumberReader( fEntree );
            nbrLigne.skip(Long.MAX_VALUE);
            int nbrLigneFichier = nbrLigne.getLineNumber();
            nbrLigneFichier = nbrLigneFichier + 1;
            entree = new BufferedReader( fEntree2 );
            tableau = new Cars[nbrLigneFichier/5];
            System.out.println( tableau.length );
            for(int i=0;i<nbrLigneFichier/5;i++) {
                String type = entree.readLine();
                type.trim();
                int posType = Cars.obtenirCode(type, 't');

                String couleur = entree.readLine();
                couleur.trim();
                int posCouleur = Cars.obtenirCode(couleur, 'c');

                int pointure = Integer.parseInt(entree.readLine());
                double prix = Double.parseDouble(entree.readLine());
                boolean neuf = Boolean.parseBoolean(entree.readLine());
                System.out.println(i);
                tableau[i] = new Cars(posType,posCouleur,pointure,prix,neuf);
                tableau[i].toString();
            }
            entree.close();
            nbrLigne.close();
        } catch ( IOException e ) {
            System.out.println( MessagesTp3.FICHIER_EXISTE_PAS );
        }

        do {            
            System.out.println( MessagesTp3.AJOUTER_PAIRE );
            System.out.println( MessagesTp3.SUPPRIMER_PAIRE );
            System.out.println( MessagesTp3.AFFICHER_PAIRES );
            System.out.println( MessagesTp3.QUITTER  );
            System.out.println( MessagesTp3.VOTRE_CHOIX ); 
            cmd = Clavier.lireInt();

            switch (cmd) {
                case 1:
                break;
                case 2:
                break;
                case 3:
                System.out.println( MessagesTp3.LISTE_CHAUSSURES );                
                for(int i=0;i<tableau.length;i++) { // This line gives me a msg of "variable tableau might not been initialized"
                    tableau[i].toString();
                }        
                break;
                case 9:
                break;
                default:
                System.out.println( MessagesTp3.CHOIX_NONVALIDE );
                break;
            }

        } while ( !(cmd == 9) );

        System.out.println( MessagesTp3.FIN_PROGRAMME );
    } // main

    public static void enregistrerPaires () {
    }

    public static void ajouterPaires () {
    }

    public static void suprimerPaires () {
    }
}

Answer 1

Actually try and catch does not limit the scope, but what the compiler is saying is that there might have been an exception thrown before initializing the variable inside the try catch block.

In that case the exception is thrown and caught, the variable is not initialized and then the code would continue. But further on, we get to the line with compilation error, where the variable would not have been initialized.

The compiler detects this possibility and throws an error, the solution is for example to initialise the variable with the empty array:

Cars [] tableau = {};