Question

Could you please point out where is the bug in my code?

I have a simple text file with the following data structure:

something1
something2
something3
...

It results a String[] where every element is the last element of the file. I can’t find the mistake, but it goes wrong somewhere around the line.setLength(0);

Any ideas?

public String[] readText() throws IOException {
    InputStream file = getClass().getResourceAsStream("/questions.txt");
    DataInputStream in = new DataInputStream(file);

    StringBuffer line = new StringBuffer();
    Vector lines = new Vector();

    int c;
    try {
        while( ( c = in.read()) != -1 ) {
            if ((char)c == '\n') {
                if (line.length() > 0) {
                    // debug
                    //System.out.println(line.toString());
                    lines.addElement(line);
                    line.setLength(0);
                }
            }
            else{
                line.append((char)c);
            }
        }
        if(line.length() > 0){
            lines.addElement(line);
            line.setLength(0);
        }

        String[] splitArray = new String[lines.size()];
        for (int i = 0; i < splitArray.length; i++) {
            splitArray[i] = lines.elementAt(i).toString();
        }
        return splitArray;

    } catch(Exception e) {
        System.out.println(e.getMessage());
        return null;
    } finally {
        in.close();
    }
}

Answer 1

I see one obvious error – you’re storing the same StringBuffer instance multiple times in the Vector, and you clear the same StringBuffer instance with setLength(0). I’m guesing you want to do something like this

 StringBuffer s = new StringBuffer();
 Vector v = new Vector();

 ...
 String bufferContents = s.toString();
 v.addElement(bufferContents);
 s.setLength(0);
 // now it's ok to reuse s
 ...