You are not passing the array object to sort method. Try the following code:
public class SortTest {
public void sort(String[] array) {
String insert;
for (int next = 1; next < array.length; next++) {
insert = array[next];
int moveItem = next;
while (moveItem > 0 && array[moveItem - 1].compareTo(insert) > 0) {
array[moveItem] = array[moveItem - 1];
moveItem--;
}
array[moveItem] = insert;
}
}
public static void main(String[] args) {
SortTest stringSort = new SortTest();
String[] array = { "aaa", "ccc", "eee", "zzz", "bbb" };
//call sorting
stringSort.sort(array);
//print the sorted array values
for (int i = 0; i < array.length; i++) {
System.out.println(array[i]);
}
}
}
solved NullPointerException error in Insertion sort [closed]