Get the element index
int indexOf(Object o)- Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.
int lastIndexOf(Object o)- Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.
import java.util.ArrayList;
import java.util.List;
public class Main {
public static void main(String[] args) {
List list = new ArrayList();
list.add("1");
list.add("2");
list.add("3");
list.add("java2s.com");
System.out.println(list.indexOf("java2s.com"));
}
}
The output:
3