String Sorting HELP

[xxbow-pkerxx]

Im a newer java programmer and i need major help the problem is that i keep getting an error (using drjava)

the error

NullPointerException:
at java.lang.String.compareTo(Unknown Source)
at insert1_1000.insertSort(insert1_1000.java:53)
at insert1_1000.main(insert1_1000.java:32)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)

the code:

code:

import java.io.*; class insert1_1000 {   public static void main (String [] args){         FileReader fileIn;     BufferedReader buffer;             int size=6000; // array size     String [] array = new String [size]; // array     int time;         try{ // read file in to array       fileIn = new FileReader ("words1.txt");       buffer = new BufferedReader (fileIn);             for (int i=0; i < size; i++){               array [i]= buffer.readLine ();          fileIn.close ();       }           }catch (IOException err){};           time=insertSort (array); // send array in to methord         System.out.println ("it took "+time);       }// end main     public static int insertSort (String [] array) {     String temp;//creates a variable to store the number to be sorted     int current=0;//creates a variable to store the current element being sorted in the array     int size = 1000;              long startTime = System.currentTimeMillis ();// start timer           for (int i=0; i<size; i++) {             current=i;//makes current the element of the number to be sorted       temp=array[i];//stores the nubmer to be sorted       //Loop will continue until it reaches 1 or the spot is found within the array             while (current>0 && array[current-1].compareTo (temp) > 0 ) {         array[current]=array[current-1];//shifts the next number to current spot         current--;//moves to next current       }       array[current]=temp;//puts the number to be sorted into its element     }         int elapsedTime= (int)(System.currentTimeMillis()-startTime);         return elapsedTime;       }   }// end class

[/code]

[xxbow-pkerxx]

please reply to me here or via e-mail

Taha1234567890@hotmail.com

[McKenzie]

Attach the data file. I tried putting empty strings in the array and it stops it from crashing. I'd guess you don't have 6000 lines in your file, or the file is not in the same folder.

I find the placement of

code:

fileIn.close ();

odd, but It won't cause your problem.

[xxbow-pkerxx]

heres the data files

if testing 3 of them

[HellblazerX]

My guess would be in this line:

code:

while (current>0 && array[current-1].compareTo (temp) > 0 ) {

Since you started with current being 0, current - 1 will give you -1, so you'll be comparing with something that doesn't exist. I think Java will check all conditions inside the parentheses, regardless of whether the first condition is true or not.

[McKenzie]

Oops,

The FileIn.close() is causing the problem. Your program will read in the first 767 lines then die with it there. Just place it after your for loop. I haven't even looked at your sort, so it may or may not work.