Null pointer Exception when using split

Question

I have been getting a null pointer exception at the split statement. I have initialised all_data1 variable, which when using a split must be an array. Please suggest what am I doing wrong... This is the code for your reference...

    test_cases = t_inp.nextInt();      //input test cases
    for(i=0;i<test_cases;i++)
    {
         String all_data = "";
         all_data = d_inp.readLine();
         all_data1 = all_data.split("\\s+");
         up_bnd[i] = Integer.parseInt(all_data1[i]);
         lw_bnd[i] = Integer.parseInt(all_data1[i+1]);
         Arrays.fill(all_data1, "");
         System.out.println(up_bnd);
         System.out.println(lw_bnd);

    }

You'll have to be more specific about what is going into `all_data`, you could be getting the exception because `.readLine()` isn't catching any input so there's nothing to split. — px06, Nov 17 '16 at 11:39
Initialize all_data to "" (null character) first, then use readLine() and split... it is possible to there were no line to be read by d_inp and all_data become null and that causes the exception — Sajad, Nov 17 '16 at 11:40
`readline()` can return **null** if the end of the stream has been reached. — Saurav Sahu, Nov 17 '16 at 11:40

score 3 · Answer 1 · answered Nov 17 '16 at 11:43

It depends on what you get from the the input reading.

I presume you are using BufferedReader, which has readLine.

The javadoc states:

 /**
     * Reads a line of text.  A line is considered to be terminated by any one
     * of a line feed ('\n'), a carriage return ('\r'), or a carriage return
     * followed immediately by a linefeed.
     *
     * @return     A String containing the contents of the line, not including
     *             any line-termination characters, or null if the end of the
     *             stream has been reached
     *
     * @exception  IOException  If an I/O error occurs
     *
     * @see java.nio.file.Files#readAllLines
     */
    public String readLine() throws IOException {
        return readLine(false);
    }

So either you get a EOL character or your stream has reached his end.

If from your input get new lines, then you could use readLine(boolean ignoreLF) which will ignore EOL characters.

Null pointer Exception when using split

1 Answers1