I am trying to self implement a sorting method to put the objects in a self-created Doubly Linked List in alphabetical order. I am however receiving a null pointer exception on the part that iterates through the letters in case the first few letters are equal. What am I doing wrong?

```
for(int i=0; i<n-1; i++) {
for(int j=i+1; j<n; j++) {
for(int k = 0; k<current.getName().length() && k<next.getName().length(); k++) {
int char1 = (int) current.getName().charAt(k);
int char2 = (int) next.getName().charAt(k);
if(char2 > char1) {
temp = current;
current = next;
next = temp;
break;
}
}
next = next.getRight();
}
current = current.getRight();
}
```

Thank you very much.