I have a problem that my program is writing only single line from the dataset whereas I want to write whole data from the data file to be read and written on the screen. Somebody help me.

This is my program:

import java.io.*;
import java.util.*;
class QueryAnswering
int rowmax = 100;
int colmax = 17;
ArrayList data;
StringTokenizer strTokenizer;
String dataSetFileName = new String("data.txt");
File outputFile;
FileWriter out;
BufferedWriter outbuf;
public void readdata(String line1, int row) {
strTokenizer = new StringTokenizer(line1);
int[] rowData = new int[colmax];
for (int col = 0; col < colmax; col++) {
rowData[col] = Integer.parseInt(strTokenizer.nextToken());

void readDataFile() {
File inputFile;
FileReader in;
BufferedReader inbuf;
int i = 0;
String line = null;
try {
inputFile = new File(this.dataSetFileName);
in = new FileReader(inputFile);
inbuf = new BufferedReader(in);
if ((rowmax == 0) || (colmax == 0)) {
line = inbuf.readLine();
strTokenizer = new StringTokenizer(line);
rowmax = Integer.parseInt(strTokenizer.nextToken());
colmax = Integer.parseInt(strTokenizer.nextToken());
data = new ArrayList();
while (i < rowmax) {
line = inbuf.readLine();
readdata(line, i);
} catch (Exception ex) {
System.out.println(line + i);


public static void main(String[] args) throws IOException {
QueryAnswering d = new QueryAnswering();



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What exactly is this program supposed to do? Please post how the data should look in it's correct form.

I solved the above problem.
I want to read random lines with few selected columns from text file, can you give idea of how to do it.


//Pre conditions: MAX_LINES is an interger that "knows" the number of lines the file has
//heres a little something, its more like psedo code

...Somewhere in the method...
int randomLine = nextInt(MAX_LINES); // Gets a random interger from 0 to end of file

while (int i = 0; i < randomLine; i++)
input.readLine(); // goes to the the random line - 1

String line = input.readLine()); // now that we're at random line -1 read it again and it will be the random line, now actually store the line.
...Do something with the line read in...

hope thats helpful, not sure on the columns :sad:

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