Hashcode value for Map Entry

As per javadocs hashcode for a map.entry is defined as : int hashCode() Returns the hash code value for this map entry. The hash code of a map entry e is defined to be: (e.getKey()==null ? 0 : …

How could a LinkedHashMap fail to find an entry produced by an iterator?

Under what circumstances given a correct implementation of hashCode and equals() can the following code return false? myLinkedHashMap.containsKey(myLinkedHashMap.keySet().iterator().next())

Why doesn’t String’s hashCode() cache 0?

I noticed in the Java 6 source code for String that hashCode only caches values other than 0. The difference in performance is exhibited by the following snippet: public class Main{ static void …