Why check if (lastRet < cursor) in AbstractList's iterator's remove() method?

Question

I'm reading openjdk AbstractList's iterator part. I couldn't figure out what the point is to check if (lastRet < cursor), which is always true to me.

Here, lastRet is the index of the value last returned by next(), and cursor is the index of the value to be returned by next().

The code is below:

public void remove() {
    if (lastRet < 0) {...} // throw exception
    checkForComodification();
    try {
        AbstractList.this.remove(lastRet);
        if (lastRet < cursor) // WHY??????????
            cursor--;
        lastRet = -1;
        expectedModCount = modCount;
    } catch (...) {
        ... // some exception
    }
 }

Answer 1

Using the code in the link provided by Spotted: http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/8u40-b25/java/util/AbstractList.java#AbstractList.Itr.remove%28%29

The code appears in the nested class Itr. There's another nested class ListItr that extends Itr. ListItr adds some new methods, but does not override remove(), which means that the code for remove() is the same in Itr and ListItr.

In ListItr, the previous() method sets lastRet and cursor to the same thing. Therefore, it is not always true that lastRet < cursor when remove() is called. It appears to always be true for a regular Itr, but not in a ListItr.