DouKaku?

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;

public class Answer33 {
    public static void main(String[] args) {
        String str = "\"aaa\",\"b\nbb\",\"ccc\",zzz,\"y\"\"Y\"\"y\",xxx";
        CSVDataReader reader = new CSVDataReader(new StringReader(str));
        try {
            while (true) {
                int cell = reader.getCellNumber();
                String s = reader.readCell();
                if (s == null) break;
                
                System.out.println(cell + " => " + s);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

class CSVDataReader extends BufferedReader {
    private int cellCount_;
    
    public CSVDataReader(Reader reader) {
        super(reader);
        cellCount_ = 1;
    }

    public int getCellNumber() {
        return cellCount_;
    }

    public String readCell() throws IOException {
        int c = read();
        if (c < 0) return null;
        cellCount_++;

        StringBuilder builder = new StringBuilder();
        boolean quote = (c == '"');
        if (!quote) {
            if (c == '\r' || c == '\n') return "";
            builder.append((char) c);
        }
        OUTER: while ((c = read()) >= 0) {
            if (quote) {
                INNER: switch (c) {
                case '"':
                    int next = read();
                    switch (next) {
                    case '"':
                        builder.append('"');
                        break INNER;
                    case ',':
                        break OUTER;
                    default:
                        throw new IllegalStateException();
                    }
                default:
                    builder.append((char) c);
                }
            } else {
                switch (c) {
                case ',':
                case '\r':
                case '\n':
                    break OUTER;
                case '"':
                    throw new IllegalStateException();
                default:
                    builder.append((char) c);
                }
            }
        }
        return builder.toString();
    }
}