Algorithm (Interesting) Programming in Java

Question

Hi,
I have a String concat = "ABC:DEF:GHIJ:KLMN". I need to parse this in such a way that I need to store the details in the hashtable as follows.
ht.put("ABC", DEF"); and ht.put("GHIJ", "KLMN"); I have written a code that works, but thats not efficient. I have another code that fails because of the last condition. I am enlosing the code that fails for the last condition. Could abybody provide me an efficient way to do this.
//Code that fails for last String.
String concat = "ABC:DEF:GHIJ:KLMN:OPQ:RST";
int length = concat.length();
int j;
for(; length > 0 ;)
     j = concat.indexOf(':');
String key = concat.substring(0, j);
     System.out.println("Key " + key);
     concat = concat.substring(j + 1, length);
     System.out.println("Concat " + concat);
     length = concat.length();
     System.out.println("length " + length);
     j = concat.indexOf(':');
     String value = concat.substring(0, j);
     System.out.println("Value " + value);
     concat = concat.substring(j + 1, length);
     System.out.println("Concat " + concat);
     length = concat.length();
     System.out.println("length " + length);
//Code that works but not effiecient
String concat = "ABC:DEF:GHIJ:KLMN";
          Hashtable ht = new Hashtable();
          StringTokenizer str = new StringTokenizer(concat, ":");
          int count = str.countTokens();
          String v=new String();
          String Key=new String();
          String val=new String();
          for(int i = 0; i < count; i++)
               v=str.nextToken();;
               if(i%2==0)
                    Key=v;
               else
                    val=v;
          if(i%2 != 0)
               System.out.println("Keys " + Key + "Val " + val);
               ht.put(Key, val);

Answer 1

Sorry, the right way is: (note that countTokens() should be a method, not a member variable.
String tst "ABCD:DEF:GHIJ:KLM";
StringTokenizer stok = new StringTokenizer(tst, ":");
while(stok.countTokens() > 1) {
    ht.put(stok.nextElement(), stok.nextElement());