Array of strings in Java NULL pointer exception -

i want make array of strings

i not have fixed size it

as must initialized, intialize null .. give java null pointer exception ???

in part of code , loop on array print contents.. how on error without having fixed size

   public static string[] suggest(string query, file file) throws filenotfoundexception {     scanner sc2 = new scanner(file);     longestcommonsubsequence obj = new longestcommonsubsequence();     string result=null;     string matchedlist[]=null;     int k=0;      while (sc2.hasnextline())      {         scanner s2 = new scanner(sc2.nextline());         while (s2.hasnext())              {             string s = s2.next();             //system.out.println(s);             result = obj.lcs(query, s);                  if(!result.equals("no match"))                 {matchedlist[k].equals(result); k++;}              }         return matchedlist;     }     return matchedlist; } 

if don't know size, list better.

to avoid npe, have initialize list :

list<string> matchedlist = new arraylist<string>();  

arraylist example, can use king of list needed.

and element instead of matchedlist[index] have :

macthedlist.get(index); 

so our code :

public static string[] suggest(string query, file file) throws filenotfoundexception { ... list<string> matchedlist= new arraylist<string>(); ...  while (sc2.hasnextline())  {     scanner s2 = new scanner(sc2.nextline());     while (s2.hasnext())      {         ...         if(!result.equals("no match")){           //this line strange. see explanation below           matchedlist.get(k).equals(result);           k++;          }     }     return matchedlist; } return matchedlist; } 

there strange in code :

matchedlist.get(k).equals(result); 

when that, compare both value , return true or false. it's possible want add value on list, in case have :

matchedlist.add(result);