How to overrides some functions in HashMap.java - hashmap

Question

1)Reading the code of HashMap.java. In line 762, the annotation says subclass overrides this to alter the behavior of put method. However, the function void addEntry(int,K,V,int) is a private function. How can it be overrided by a subclass?
/**
758 * Adds a new entry with the specified key, value and hash code to
759 * the specified bucket. It is the responsibility of this
760 * method to resize the table if appropriate.
761 *
762 * Subclass overrides this to alter the behavior of put method.
763 */
764 void addEntry(int hash, K key, V value, int bucketIndex) {
765 Entry<K,V> e = table[bucketIndex];
766 table[bucketIndex] = new Entry<>(hash, key, value, e);
767 if (size++ >= threshold)
768 resize(2 * table.length);
2) In line 746 and 753, the two functions recordAccess and recordRemoval remain empty. So how can a subclass override these two functions?
static class Entry<K,V> implements Map.Entry<K,V> {
688 final K key;
689 V value;
690 Entry<K,V> next;
691 final int hash;
...
/**
742 * This method is invoked whenever the value in an entry is
743 * overwritten by an invocation of put(k,v) for a key k that's already
744 * in the HashMap.
745 */
746 void recordAccess(HashMap<K,V> m) {
747 }
748
749 /**
750 * This method is invoked whenever the entry is
751 * removed from the table.
752 */
753 void recordRemoval(HashMap<K,V> m) {
754 }
755 }

Answer 1

These methods are not private.
The accessibility when not specified is so called "package private". In particular, these methods can be overridden by other classes in the same package. The reason is probably that the Java authors want to be sure they can change/rename/replace this method anytime without breaking any application. When you are not sure that the API is good, it makes a lot of sense to keep those parts "package private", gather some experience with extending the class this way, and once you are sure the API is going to stay that way you can still make them public later on. However, you can't make them private, otherwise your own classes would also not be allowed to extend them!
To get a true private method, you should use the keyword private. Without any specification, the default is this so called "package private", and for public interfaces it even is public when nothing is specified.
If you are using eclipse, try Ctrl+T on the method name to see if any class overrides them.