https://github.com/eclipse/eclipse-collections/eclipse-collections: Eclipse Collections is a collections framework for Java. It has JDK-compatible List, Set and Map implementations with a rich API and set of utility classes that work with any JDK compatible Collections, Arrays, Maps or Strings. The iteration protocol was inspired by the Smalltalk collection framework.
  • Craig P. Motlin
  • Donald Raab
  • Mohammad A. Rezaei
  • Hiroshi Ito
  • Nikhil J. Nanivadekar 
public final class org.eclipse.collections.impl.factory.Multimaps
  minor version: 0
  major version: 59
  flags: flags: (0x0031) ACC_PUBLIC, ACC_FINAL, ACC_SUPER
  this_class: org.eclipse.collections.impl.factory.Multimaps
  super_class: java.lang.Object
{
  public static final org.eclipse.collections.impl.factory.Multimaps$ImmutableMultimaps immutable;
    descriptor: Lorg/eclipse/collections/impl/factory/Multimaps$ImmutableMultimaps;
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL

  public static final org.eclipse.collections.impl.factory.Multimaps$MutableMultimaps mutable;
    descriptor: Lorg/eclipse/collections/impl/factory/Multimaps$MutableMultimaps;
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL

  static void <clinit>();
    descriptor: ()V
    flags: (0x0008) ACC_STATIC
    Code:
      stack=2, locals=0, args_size=0
         0: .line 38
            new org.eclipse.collections.impl.factory.Multimaps$ImmutableMultimaps
            dup
            invokespecial org.eclipse.collections.impl.factory.Multimaps$ImmutableMultimaps.<init>:()V
            putstatic org.eclipse.collections.impl.factory.Multimaps.immutable:Lorg/eclipse/collections/impl/factory/Multimaps$ImmutableMultimaps;
         1: .line 39
            new org.eclipse.collections.impl.factory.Multimaps$MutableMultimaps
            dup
            invokespecial org.eclipse.collections.impl.factory.Multimaps$MutableMultimaps.<init>:()V
            putstatic org.eclipse.collections.impl.factory.Multimaps.mutable:Lorg/eclipse/collections/impl/factory/Multimaps$MutableMultimaps;
            return
      LocalVariableTable:
        Start  End  Slot  Name  Signature

  private void <init>();
    descriptor: ()V
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // org.eclipse.collections.impl.factory.Multimaps this
         0: .line 41
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 43
            new java.lang.AssertionError
            dup
            ldc "Suppress default constructor for noninstantiability"
            invokespecial java.lang.AssertionError.<init>:(Ljava/lang/Object;)V
            athrow
        end local 0 // org.eclipse.collections.impl.factory.Multimaps this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lorg/eclipse/collections/impl/factory/Multimaps;
}
SourceFile: "Multimaps.java"
NestMembers:
  org.eclipse.collections.impl.factory.Multimaps$ImmutableMultimaps  org.eclipse.collections.impl.factory.Multimaps$ImmutableMultimaps$ImmutableBagMultimapFactory  org.eclipse.collections.impl.factory.Multimaps$ImmutableMultimaps$ImmutableListMultimapFactory  org.eclipse.collections.impl.factory.Multimaps$ImmutableMultimaps$ImmutableSetMultimapFactory  org.eclipse.collections.impl.factory.Multimaps$ImmutableMultimaps$ImmutableSortedSetMultimapFactory  org.eclipse.collections.impl.factory.Multimaps$MutableMultimaps  org.eclipse.collections.impl.factory.Multimaps$MutableMultimaps$MutableBagMultimapFactory  org.eclipse.collections.impl.factory.Multimaps$MutableMultimaps$MutableListMultimapFactory  org.eclipse.collections.impl.factory.Multimaps$MutableMultimaps$MutableSetMultimapFactory  org.eclipse.collections.impl.factory.Multimaps$MutableMultimaps$MutableSortedBagMultimapFactory  org.eclipse.collections.impl.factory.Multimaps$MutableMultimaps$MutableSortedSetMultimapFactory
InnerClasses:
  public final ImmutableMultimaps = org.eclipse.collections.impl.factory.Multimaps$ImmutableMultimaps of org.eclipse.collections.impl.factory.Multimaps
  public final MutableMultimaps = org.eclipse.collections.impl.factory.Multimaps$MutableMultimaps of org.eclipse.collections.impl.factory.Multimaps