Java tutorial
import java.io.BufferedReader; import java.io.FileReader; import java.io.IOException; import java.util.Enumeration; import java.util.Hashtable; import java.util.Map; import java.util.StringTokenizer; public class MainClass { static final Integer ONE = new Integer(1); public static void main(String args[]) throws IOException { Hashtable map = new Hashtable(); FileReader fr = new FileReader(args[0]); BufferedReader br = new BufferedReader(fr); String line; while ((line = br.readLine()) != null) { processLine(line, map); } Enumeration e = map.keys(); while (e.hasMoreElements()) { String key = (String) e.nextElement(); System.out.println(key + " : " + map.get(key)); } } static void processLine(String line, Map map) { StringTokenizer st = new StringTokenizer(line); while (st.hasMoreTokens()) { addWord(map, st.nextToken()); } } static void addWord(Map map, String word) { Object obj = map.get(word); if (obj == null) { map.put(word, ONE); } else { int i = ((Integer) obj).intValue() + 1; map.put(word, new Integer(i)); } } }