http://fastutil.di.unimi.it/: fastutil extends the Java Collections Framework by providing type-specific maps, sets, lists and priority queues with a small memory footprint and fast access and insertion; provides also big (64-bit) arrays, sets and lists, and fast, practical I/O classes for binary and text files.
  • Sebastiano Vigna 
package it.unimi.dsi.fastutil;

/*
 * Copyright (C) 2003-2019 Paolo Boldi and Sebastiano Vigna
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


 An abstract class providing basic methods for implementing the PriorityQueue interface. 
Deprecated:As of fastutil 8 this class is no longer necessary, as its previous abstract methods are now default methods of PriorityQueue.
/**  An abstract class providing basic methods for implementing the {@link PriorityQueue} interface.
 *
 * @deprecated As of fastutil 8 this class is no longer necessary, as its previous abstract
 * methods are now default methods of {@link PriorityQueue}.
 */
@Deprecated
public abstract class AbstractPriorityQueue<K> implements PriorityQueue<K> {}