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String Sorting error

Siddhesh Desai

Joined: Jun 28, 2004
Posts: 9
import java.util.*;
class TestString
public static void main(String args[])
throws IOException
String str[]= new String[10];
//int array[]=new int[10];
BufferedReader br = new BufferedReader(new InputStreamReader(;
for(int i=0;i<5;i++)
for (int i=0; i<str.length-1; i++) {
for (int j=i+1; j<str.length; j++) {
if (str[i].compareTo(str[j]) > 0) {
String temp=str[j]; str[j]=str[i]; str[i]=temp;
Program complies but following Run Time errors occors
Exception in thread "main" java.lang.NullPointerException
at java.lang.String.compareTo(
at TestString.main(
please help me
Michael Dunn
Ranch Hand

Joined: Jun 09, 2003
Posts: 4632
change this
String str[]= new String[10];

to this
String str[]= new String[5];

or change this
for(int i=0;i<5;i++) str[i]=br.readLine();

to this
for(int i=0;i<10;i++) str[i]=br.readLine();
I agree. Here's the link:
subject: String Sorting error
jQuery in Action, 3rd edition