Exception in thread "main" java.lang.NullPointerException

[javagirl24]

I am getting this exception in the code below for not initializing arraylist.. could someone please help me with this..:(
this problem is in g[i].v.add(vv);


class graph
{

public ArrayList<Integer[]> v=new ArrayList<Integer[]>();
public ArrayList<Integer[]> e=new ArrayList<Integer[]>();


}


public class main {



public static void main(String[] args) {

Integer vv[]=new Integer[2];
Integer ee[]=new Integer[3];
graph g[]=new graph[1000];
int i=-1;
String t="t";
String v="v";
String e="e";
FileInputStream fstream;
try {
fstream = new FileInputStream("graph1.txt");


DataInputStream in = new DataInputStream(fstream);
BufferedReader b = new BufferedReader(new InputStreamReader(in));

String line;

try {
while ((line = b.readLine()) != null) {
StringTokenizer st = new StringTokenizer(line);

if(t.equals(st.nextToken()))
{
i++;

}
line = b.readLine();
System.out.println(line);
StringTokenizer st1 = new StringTokenizer(line);

if(v.equals(st1.nextToken()))
{

vv[0]=Integer.parseInt(st1.nextToken());
vv[1]=Integer.parseInt(st1.nextToken());
g[i].v.add(vv);
}
line = b.readLine();
StringTokenizer st2 = new StringTokenizer(line);

if(e.equals(st2.nextToken()))
{
ee[0]=Integer.parseInt(st2.nextToken());
ee[1]=Integer.parseInt(st2.nextToken());
ee[2]=Integer.parseInt(st2.nextToken());
g[i].e.add(ee);

}


}
} catch (IOException ex) {
Logger.getLogger(main.class.getName()).log(Level.S EVERE, null, ex);
}
} catch (FileNotFoundException ex) {
Logger.getLogger(main.class.getName()).log(Level.S EVERE, null, ex);
}

}}

[Norm]

What variable has a null value?

Please post the full text of the error message.


Some bad practices I see are:
using variable names that are only 1 character long
having more than one variable with the same name: e & v

You need to fix those.

Also use code tags: http://www.java-forums.org/misc.php?do=bbcode#code

[DarrylBurke]

Duplicate of Exception in thread "main" java.lang.NullPointerException

Closing the thread and banning the javagirl24 account.

db

THREAD CLOSED