I'm looking at a java hangman game here: https://github.com/leleah/EvilHangman/blob/master/EvilHangman.java

The code in particular is this:

Iterator<Entry<List<Integer>, Set<String>>> k = partitions.entrySet().iterator();
while (k.hasNext())
{
    Entry<?, ?> pair = (Entry<?, ?>)k.next();
    int sizeOfSet = ((Set<String>)pair.getValue()).size();
    if (sizeOfSet > biggestPartitionSize)
    {
        biggestPartitionSize = sizeOfSet;
    }
}

Now my question. My google foo is weak I guess, I cannot find much on Entry sets other than the java doc itself. Is is just a temporary copy of the map? And I cannot find any info at all on the syntax:

Entry<?, ?>

Can anyone explain or point me toward an explanation of what is going on with those question marks? Thanks in advanced.