Question

This is my first post here so feel free to point me in the right direction regarding formulating a question here.

My issue is with the java.util.PriorityQueue.

I have a queue that I initialize;

    myComparable comp = new myComparable();

    PriorityQueue<someObject> prioritized = new PriorityQueue<someObject>(11, comp);

I dont think it matters for the question what is in my queue or how myComparable is implemented.

I then get unexpected output:

prioritizedObject = prioritized.poll();

for(someObject otherObject : prioritized)
{
    System.out.println(comp.compare(prioritizedObject, otherObject));
    System.out.println(comp.equals(prioritizedObject, otherObject));

}

For one object in the list this prints:
1
false

How can this be? How can I poll() an object from the queue while the comparator Im using says that another object in the queue is smaller?

Answer 1

In case everything else is right (no concurrent pushes, not getting the test wrong), I could imagine two reasons:

• the objects change in a way affecting their order (forbidden)
• the comparator is wrong (not transitive or whatever)