stringbuffer :nullpointerexception

[f. nikita thomas]

hey guys,

import java.util.*;
import java.io.*;
 
public class d7
{
   private static BufferedReader ifile;
   private static PrintWriter ofile;
   private static StringBuffer sb;
   private static String s0;
 
   public static String removepunct(String s)
   {
for(int i = 0;i < s.length();i++)
{
   if(Character.isLetter(s.charAt(i)))
      sb.append(s.charAt(i));// <- nullpointerexception here!
}
return sb.toString();
   }
 
   public static void main(String[] args) throws IOException
   {
BufferedReader ifile = new BufferedReader(new FileReader(args[0]));
PrintWriter ofile = new PrintWriter(args[1]);
while((s0 = ifile.readLine()) != null)
      ofile.println(removepunct(s0));
ifile.close();
ofile.close();
  }
}   

this is the first time i have used StringBuffer. if anyone is still awake ... thanks.

nikita

[Balasubramani Dharmalingam]

Variable sb is not yet initialized, default value will be null. So you are getting null pointer exception. Replace the sb declaration with following code.Then it should work

   private static StringBuffer sb = new StringBuffer();  

[f. nikita thomas]

shows you how tired i am. thanks Balasubramani. namaste.
[ April 09, 2008: Message edited by: f. nikita thomas ]

[David O'Meara]

Originally posted by f. nikita thomas:
shows you how tired i am. thanks Balasubramani. namaste.

Rest, the code will wait for you

[f. nikita thomas]

couldn't wait ...

import java.util.*;
import java.io.*;
 
public class d7
{
   private static BufferedReader ifile;
   private static PrintWriter ofile;
   private static StringBuffer sb = new StringBuffer();
   private static String s0;
 
   // removepunct() will remove whitespace and punctuation
   public static String removepunct(String s)
   { 
sb.setLength(0);// <- clear the buffer
for(int i = 0;i < s.length();i++)
{
   if(Character.isLetter(s.charAt(i)))
      sb.append(s.charAt(i));
}
return sb.toString();
   }
 
   public static void main(String[] args) throws IOException
   {
BufferedReader ifile = new BufferedReader(new FileReader(args[0]));
PrintWriter ofile = new PrintWriter(args[1]);
while((s0 = ifile.readLine()) != null)
      ofile.println(removepunct(s0));
ifile.close();
ofile.close();
  }
}

unfortunately i set the bar high for myself. this will teach me some humility. but your right, enough for now. shalom.

nikita