PriorityQueue.grow has this code:

             if (newlen >= Integer.MAX_VALUE / 2) // avoid overflow
                newlen = Integer.MAX_VALUE;
            else
                newlen <<= 2;

That shift grows by 4. The intended action was certainly

 newlen <<= 1;

The current code fails when the internal array is between
Integer.MAX_VALUE/4 and Integer.MAX_VALUE/2,
and is needlessly wasteful of memory in other cases.