Help With TreeMap Warning (Noob?)

Sorry if I am asking a dumb question - but I am having a problem, an usual
warning is coming up when I compile my simple program.

When I compile

....\Desktop>javac edit_dist.java
Note: edit_dist.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

Recompiling

E:\Documents and Settings\Luc\Desktop>javac edit_dist.java -Xlint:unchecked
edit_dist.java:41: warning: [unchecked] unchecked call to put(K,V) as a
member of the raw type java.util.TreeMap
                mtm.put(myCurKey, new Integer(min));
                       ^

Here is my code

import java.util.*;
import java.lang.*;
import java.math.*;

public class edit_dist{
 TreeMap mtm = null;
 edit_dist(){
  mtm = new TreeMap<String, Integer>();
 }
 public static int naive_editDistance(String Source, String Dest){
  if(Source.equals("") || Dest.equals(""))
   return Dest.length() + Source.length();
  if(Source.charAt(0) == Dest.charAt(0))
   return naive_editDistance(Source.substring(1), Dest.substring(1));
  int min = 536870911; //arbitrarily large number above max length of
string
  for(int i=0;i<2;i++)
   for(int j=(i!=0?0:1);j<2;j++)
    min = Math.min (min,
          1 + naive_editDistance(Source.substring(i),

Dest.substring(j)));
  return min; // :)
 }
 private static String makeLen(String in, int OSL){
  int a = OSL - in.length();
  for(int i=0;i<a;i++)
   in+=(char) 1;
  return in;
 }
 int memoize_editDistance(String Source, String Dest, int OSL){
  if(Source.equals("") || Dest.equals(""))
   return Dest.length() + Source.length();
  String myCurKey = makeLen(Source, OSL) + Dest;
  if(mtm.containsValue(myCurKey))
   return ((Integer)mtm.get(myCurKey)).intValue();
  if(Source.charAt(0) == Dest.charAt(0))
   return naive_editDistance(Source.substring(1), Dest.substring(1));
  int min = 536870911; //arbitrarily large number above max length of
string
  for(int i=0;i<2;i++)
   for(int j=(i!=0?0:1);j<2;j++)
    min = Math.min (min,
          1 + naive_editDistance(Source.substring(i),

Dest.substring(j)));
  mtm.put(myCurKey, new Integer(min));
  return min; // :)
 }

 public static int memoize_editDistance(String Source, String Dest){
  return (new edit_dist()).memoize_editDistance(Source, Dest,
Source.length());

 }
 public static void main(String[] xs){
  String[] x = {"accept", "allow", "ask", "believe", "borrow", "break",
"bring",

"buy", "can/beable", "cancel", "change", "clean", "comb", "complain",
"cough", "count", "cut"};
  int[] res = {0, 5, 5, 6, 6, 5, 6, 6, 8, 4, 6, 4, 5, 7, 5, 4, 4, 5, 0, 4,
6, 4, 5,

5, 5, 9, 5, 6, 4, 5, 7, 5, 5, 5, 5, 4, 0, 7, 6, 4, 5, 3, 9, 5, 5, 5, 4, 7,
5, 5, 3, 6, 6, 7, 0,

6, 5, 5, 6, 8, 6, 6, 5, 7, 8, 7, 7, 7, 6, 4, 6, 6, 0, 4, 4, 5, 9, 6, 6, 6,
5, 7, 5, 5, 6, 5, 5,

4, 5, 4, 0, 3, 4, 8, 6, 6, 3, 5, 7, 5, 5, 5, 6, 5, 5, 5, 4, 3, 0, 4, 9, 6,
4, 5, 5, 7, 5, 4, 5,

6, 5, 3, 6, 5, 4, 4, 0, 9, 6, 6, 5, 4, 8, 4, 4, 2, 8, 9, 9, 8, 9, 8, 9, 9,
0, 5, 7, 7, 8, 8, 9,

9, 9, 4, 5, 5, 6, 6, 6, 6, 6, 5, 0, 3, 5, 5, 7, 5, 5, 5, 6, 6, 5, 6, 6, 6,
4, 6, 7, 3, 0, 4, 5,

7, 4, 4, 5, 4, 4, 5, 5, 6, 3, 5, 5, 7, 5, 4, 0, 4, 5, 4, 4, 4, 5, 5, 4, 7,
5, 5, 5, 4, 8, 5, 5,

4, 0, 5, 3, 3, 3, 7, 7, 7, 8, 7, 7, 7, 8, 8, 7, 7, 5, 5, 0, 6, 6, 7, 5, 5,
5, 7, 5, 5, 5, 4, 9,

5, 4, 4, 3, 6, 0, 2, 3, 4, 5, 5, 7, 5, 5, 4, 4, 9, 5, 4, 4, 3, 6, 2, 0, 2,
4, 5, 3, 7, 6, 5, 5,

2, 9, 5, 5, 4, 3, 7, 3, 2, 0}; //results from naive_editDistance assumed
correct
  int nc = 0;
  int lv = 0;
  for(String C : x)
   for(String Y : x)
    if((lv=memoize_editDistance(C, Y))!=res[nc++])
     System.out.println("Failed on " + C +" to " + Y + " got "

 +lv + " expecting " + res[nc-1]);

 }

}
--
LTP

:)