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 
public interface it.unimi.dsi.fastutil.longs.LongIndirectPriorityQueue extends it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Long>
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: it.unimi.dsi.fastutil.longs.LongIndirectPriorityQueue
  super_class: java.lang.Object
{
  public abstract it.unimi.dsi.fastutil.longs.LongComparator comparator();
    descriptor: ()Lit/unimi/dsi/fastutil/longs/LongComparator;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT

  public java.util.Comparator comparator();
    descriptor: ()Ljava/util/Comparator;
    flags: (0x1041) ACC_PUBLIC, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=1, locals=1, args_size=1
         0: .line 1
            aload 0
            invokeinterface it.unimi.dsi.fastutil.longs.LongIndirectPriorityQueue.comparator:()Lit/unimi/dsi/fastutil/longs/LongComparator;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature
}
Signature: Ljava/lang/Object;Lit/unimi/dsi/fastutil/IndirectPriorityQueue<Ljava/lang/Long;>;
SourceFile: "LongIndirectPriorityQueue.java"