https://github.com/google/guava/guava: Guava is a suite of core and expanded libraries that include utility classes, google's collections, io classes, and much much more. 
class com.google.common.collect.MultimapBuilder$1 extends com.google.common.collect.MultimapBuilder$MultimapBuilderWithKeys<java.lang.Object>
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.google.common.collect.MultimapBuilder$1
  super_class: com.google.common.collect.MultimapBuilder$MultimapBuilderWithKeys
{
  private final int val$expectedKeys;
    descriptor: I
    flags: (0x1012) ACC_PRIVATE, ACC_FINAL, ACC_SYNTHETIC

  void <init>(int);
    descriptor: (I)V
    flags: (0x0000) 
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.google.common.collect.MultimapBuilder$1 this
         0: .line 89
            aload 0 /* this */
            iload 1
            putfield com.google.common.collect.MultimapBuilder$1.val$expectedKeys:I
            aload 0 /* this */
            invokespecial com.google.common.collect.MultimapBuilder$MultimapBuilderWithKeys.<init>:()V
            return
        end local 0 // com.google.common.collect.MultimapBuilder$1 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/MultimapBuilder$1;
    MethodParameters:
                  Name  Flags
      val$expectedKeys  final

  <K, V> java.util.Map<K, java.util.Collection<V>> createMap();
    descriptor: ()Ljava/util/Map;
    flags: (0x0000) 
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.MultimapBuilder$1 this
         0: .line 92
            aload 0 /* this */
            getfield com.google.common.collect.MultimapBuilder$1.val$expectedKeys:I
            invokestatic com.google.common.collect.Platform.newHashMapWithExpectedSize:(I)Ljava/util/Map;
            areturn
        end local 0 // com.google.common.collect.MultimapBuilder$1 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/MultimapBuilder$1;
    Signature: <K:Ljava/lang/Object;V:Ljava/lang/Object;>()Ljava/util/Map<TK;Ljava/util/Collection<TV;>;>;
}
Signature: Lcom/google/common/collect/MultimapBuilder$MultimapBuilderWithKeys<Ljava/lang/Object;>;
SourceFile: "MultimapBuilder.java"
EnclosingMethod: com.google.common.collect.MultimapBuilder.hashKeys:(I)Lcom/google/common/collect/MultimapBuilder$MultimapBuilderWithKeys;
NestHost: com.google.common.collect.MultimapBuilder
InnerClasses:
  com.google.common.collect.MultimapBuilder$1
  public abstract MultimapBuilderWithKeys = com.google.common.collect.MultimapBuilder$MultimapBuilderWithKeys of com.google.common.collect.MultimapBuilder