Looking through the java source code, I faced with incomprehensible for me construction in the hashCode() method of the class AbstractList. This is implementation of the hashCode method for ArrayList. I don't understand how it iterates with for-each.
public int hashCode() {
int hashCode = 1;
for (E e : this) //<--???
hashCode = 31*hashCode + (e==null ? 0 : e.hashCode());
return hashCode;
}
E is the type of the element. But to which class(type) pointer this belongs?
But to which class(type) pointer this belongs?
this is the list that hashCode was called on. So the compile-time type is AbstractList<E>.
It's saying "for every element in this list, include that element's hash code in the result".
The E e refers to the generic type in that ArrayList<E> (see the E?)
Think of it as
ArrayList<String> list
for(String e : list) {
Only because you're inside the list your list becomes this
List<Person> personList = new ArrayList<Person>();
this - It will refer personList
e - It will refer object of Person class
