How do I sort records in a text file using Java?

Here's something I came up with:

import java.io.*;
import java.util.*;

public class Sort {

    public static void main(String[] args) throws Exception {
        BufferedReader reader = new BufferedReader(new FileReader("fileToRead"));
        Map<String, String> map=new TreeMap<String, String>();
        String line="";
        while((line=reader.readLine())!=null){
            map.put(getField(line),line);
        }
        reader.close();
        FileWriter writer = new FileWriter("fileToWrite");
        for(String val : map.values()){
            writer.write(val);  
            writer.write('\n');
        }
        writer.close();
    }

    private static String getField(String line) {
        return line.split(" ")[0];//extract value you want to sort on
    }
}

package com.myFiles;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;

public class FilesReaderWriter {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = null;
        PrintWriter outputStream = null;
        ArrayList<String> rows = new ArrayList<String>();

        try {
            reader  = new BufferedReader(new FileReader("Input.txt"));
            outputStream = new PrintWriter(new FileWriter("Output.txt"));

            String file;
            while ((file = reader .readLine()) != null) {
                rows.add(file);
            }
            Collections.sort(rows);
            String[] strArr= rows.toArray(new String[0]);
            for (String cur : strArr)
                outputStream.println(cur);
        } finally {
            if (reader  != null) {
                inputStream.close();
            }
            if (outputStream != null) {
                outputStream.close();
            }
        }
    }

}

Here's a pretty lazy way of doing it since you are only sorting first word:

    ArrayList<String> rows = new ArrayList<String>();
    BufferedReader reader = new BufferedReader(new FileReader("input.txt"));

    String s;
    while((s = reader.readLine())!=null)
        rows.add(s);

    Collections.sort(rows);

    FileWriter writer = new FileWriter("output.txt");
    for(String cur: rows)
        writer.write(cur+"\n");

    reader.close();
    writer.close();

Using sort:

aaron@ares ~$ sort data.txt 
Alba     Walk     20mins
Amy      Jogging  40mins
Bobby    Run      10mins
Jessica  Run      20mins

aaron@ares ~$ sort data.txt > sorted.txt
aaron@ares ~$ cat sorted.txt
Alba     Walk     20mins
Amy      Jogging  40mins
Bobby    Run      10mins
Jessica  Run      20mins

... or using python:

aaron@ares ~$ python -c "import sys; print ''.join(sorted(sys.stdin))" < data.txt > sorted.txt
aaron@ares ~$ cat sorted.txt 
Alba     Walk     20mins
Amy      Jogging  40mins
Bobby    Run      10mins
Jessica  Run      20mins