IdentityHashMap.EntrySet.toArray(Object[]) doesn't return a value which follows the type of the array which is passed in.

import java.util.*;

public class ihashmap {
    public static void main(String[] args) {
        IdentityHashMap hm = new IdentityHashMap();
        Set set = hm.entrySet();
        String[] array = (String[]) set.toArray(new String[0]);
    }
}

Compile this with 1.4.2. Running with 1.4.2 succeeds but 1.5.0 fails with

Exception in thread "main" java.lang.ClassCastException: [Ljava.lang.Object;
at ihashmap.main(ihashmap.java:7)

The code explains it all.

        public <T> T[] toArray(T[] a) {
return (T[])toArray(); // !!!!
        }