I am getting null-exception throw error in the following code. What can be the reason for it?
public static String[] CreateVocab(BufferedReader buffR) throws IOException{
String[] arr = null;
int i = 0;
arr[i]= null;
String line = new String();
while((line = buffR.readLine()) != null){
arr[i] = line;
i=i+1;
}
return arr;
}
Compiler is showing Null ponter exception in the code
arr[i]=null.
This is the cause:
String[] arr = null;
int i = 0;
arr[i]= null; // 'arr' is null
As the number of lines being read is unknown suggest using an ArrayList<String> to store the lines read, and the use ArrayList.toArray() to return a String[] (if returning an ArrayList<String> is not acceptable).
Example that returns a List<String>:
public static List<String> CreateVocab(BufferedReader buffR)
throws IOException
{
List<String> arr = new ArrayList<String>();
String line;
while((line = buffR.readLine()) != null){
arr.add(line);
}
return arr;
}
To return an array change return to:
return arr.toArray(new String[]{});
You haven't created the array - and an array won't solve your problem anyway, because it can't resize. We don't know the number of lines in advance.
Use a collection instead:
public static String[] CreateVocab(BufferedReader buffR) throws IOException{
List<String> lines = new ArrayList<String>();
String line = null;
while((line = buffR.readLine()) != null){
lines.add(line);
}
return lines.toArray(new String[]{});
}
String[] arr = null; //here you are setting arr to null
int i = 0;
arr[i]= null; // here you are trying to reference arr
