PriorityQueue is a data structure. Like SortedSet, PriorityQueue sorts also its elements based on their priorities. The elements, which have a higher priority, comes first. The type of the PriorityQueue should implement comparable or comparator interface, whose methods decides the priorities of the elements of the data structure.
//The type of the PriorityQueue is Integer.
PriorityQueue<Integer> queue = new PriorityQueue<Integer>();
//The elements are added to the PriorityQueue
queue.addAll( Arrays.asList( 9, 2, 3, 1, 3, 8 ) );
//The PriorityQueue sorts the elements by using compareTo method of the Integer Class
//The head of this queue is the least element with respect to the specified ordering
System.out.println( queue ); //The Output: [1, 2, 3, 9, 3, 8]
queue.remove();
System.out.println( queue ); //The Output: [2, 3, 3, 9, 8]
queue.remove();
System.out.println( queue ); //The Output: [3, 8, 3, 9]
queue.remove();
System.out.println( queue ); //The Output: [3, 8, 9]
queue.remove();
System.out.println( queue ); //The Output: [8, 9]
queue.remove();
System.out.println( queue ); //The Output: [9]
queue.remove();
System.out.println( queue ); //The Output: []