JAVA_Map_Auto-Boxing_Unboxing

 1 import java.util.*;
 2 public class TestMap {
 3   public static void main(String args[]) {
 4     Map m1 = new HashMap(); 
 5     Map m2 = new TreeMap();
 6     //m1.put("one",new Integer(1));
 7     m1.put("one", 1);
 8     //m1.put("two",new Integer(2));
 9     m1.put("two", 2);
10     //m1.put("three",new Integer(3));
11     m1.put("three", 3);
12     //m2.put("A",new Integer(1));
13        m2.put("A", 1);
14     //m2.put("B",new Integer(2));
15     m2.put("B", 2);
16     System.out.println(m1.size());
17     System.out.println(m1.containsKey("one"));
18     System.out.println
19         //(m2.containsValue(new Integer(1)));
20         (m2.containsValue(1));
21     if(m1.containsKey("two")) {
22       //int i = ((Integer)m1.get("two")).intValue();
23       int i = (Integer)m1.get("two");
24       System.out.println(i);
25     }
26     Map m3 = new HashMap(m1);
27     m3.putAll(m2);
28     System.out.println(m3);
29   }
30 }

 1 import java.util.*;
 2 public class TestArgsWords {
 3   //private static final Integer ONE = new Integer(1);
 4   private static final int ONE = 1;
 5   public static void main(String args[]) {
 6     Map m = new HashMap();
 7     for (int i = 0; i < args.length; i++) {
 8       //Integer freq = (Integer) m.get(args[i]);
 9       
10       int freq = (Integer) m.get(args[i]) == null ? 0 : (Integer) m.get(args[i]);
11       //m.put(args[i],(freq == null? ONE : new Integer(freq.intValue() + 1)));
12       m.put(args[i], freq==0 ? ONE : freq + 1);
13     }
14     System.out.println
15         (m.size() + " distinct words detected:");
16     System.out.println(m);
17   }
18 }