getting nullpoint exception again
 

not clear with the basics of nullpont error; trying to create student database



import java.io.*;

class student1

{

String name;

int id;

public void getdata(String name1,int id1)

{

name=name1;

id=id1;

}

public void putdata()

{

System.out.println("\t"+id+" "+name);

}

}

class student

{

public static void main(String args[])throws IOException

{

BufferedReader br= new BufferedReader(new 



InputStreamReader(System.in));

BufferedReader br1= new BufferedReader(new 



InputStreamReader(System.in));

student1[] n=new student1[10];

for(int i=0;i<5;i++)

{

n[i].getdata(br.readLine(),Integer.parseInt(br1.readLine()));

n[i].putdata();



}

}

}

Re: getting nullpoint exception again
 

The exception contains a line number, so which line is it?

Re: getting nullpoint exception again
 

java:29 line 29

thanks

Re: getting nullpoint exception again
 

And which line there is line 29?

Re: getting nullpoint exception again
 

n[i].getdata(....)

tried without using BufferedReader directly putting values but same error.Object seems to be null.

Re: getting nullpoint exception again
 

n[] is new array, has nothing in it. So n[i] has nothing in it for all values of i, so n[i].someFunction tries to call someFunction on a null value -> Exception.
Maybe initialise n[i] to new Student1() before using it?

Re: getting nullpoint exception again
 

thanks a lot a bunch it worked

Re: getting nullpoint exception again
 

Dear James

i wished you could solve this NPE too. i am trying to separate the words and print the longest. i tried using s.length but found difficult

getting error at toCompare which compares the length of strings



class maxstring1

{

public static void main(String args[]) 

{

String s1="nikhil is a good boy";

int d;int x=0;

d=s1.length();

String[] s2=new String[20]; 

char ch;

for(int i=0;i<=d-1;i++)

{

ch=s1.charAt(i);

if(ch==' ')

{

s2[i]=new String();

s2[i]=s1.substring(x,i-1);

x=i+1;

}

}

for(int i=0;i<=d-1;i++)

{

s2[i]=new String();

System.out.println(s2[i]);

if(s2[i].compareTo(max)>0)

max=s2[i];

}

System.out.println(max);

}

}

Re: getting nullpoint exception again
 

NPE is probably because max isn't defined or initialised. But you have other problems.eg: S2 is initialised to empty Strings, but you never put anything else in there before comparing them. And you compare them alphabetically, not by length.
Have a look at the split(" ") method for Strings - this will get you your words just like you need them...

EDIT: I just saw that you have already posted this problem, and a number of other posters have given the same advice already, and you don't seem to have followed it. Are you wasting my time?

Re: getting nullpoint exception again
 

[code]

i am sorry

i wanted to do it in my way. I know and remember other posts.But if you could solve the NPE problem in one case u could do it in other as well. I know the split or String tokenizer method. (i am tryng to explain for loop to one of my friend so i just took a chance if u could solve it.But its ok.
sorry again .

thanks
akulkarni