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Question about strange NullPointerException
Submitted by ybjoony on Wed, 12/23/2009 - 09:50.
This is my code about roughly counting character counts by adding lengths of the each file names given by command line arguments... Strangely, it generates NullPointerException on line 50(ch += in.readLine().length();) if implemented without the println method above it; but if I implement the println, and then run it, the method commences with no problem. I wonder why this is happening. Can somebody help?
Code is like this...
package chapter2;
import java.io.*;
public class exer13
{
public static void main(String[] args)
{
if(args.length==0)
System.out.println("Error: provide command line arguments");
for(String fileName: args){
processFile(fileName);
}
}
public static void processFile(String fileName){
FileReader theFile;
BufferedReader fileIn = null;
System.out.println( "FILE: " + fileName );
try
{
theFile = new FileReader( "C:/Users/ybjoony/workspace/book/src/chapter2/"+fileName );
fileIn = new BufferedReader( theFile );
System.out.println("Number Of Characters: " + countChar(fileIn));
}
catch( IOException e )
{ System.out.println( e ); }
finally
{
// Close the stream
try
{
if(fileIn != null )
fileIn.close( );
}
catch( IOException e )
{ }
}
}
//Somehow fails if implemented w/o println statements. catch statements doesn't seem to work.
public static int countChar(BufferedReader in)
{
int ch = 0;
if(in==null) throw new NullPointerException();
try{
System.out.println(in.readLine());
while(in.readLine()!=null){
ch += in.readLine().length();
}
}catch(IOException e){System.out.println(e);}
//catch(NullPointerException e){System.out.println(e);}
return ch;
}
}