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.Maps$3 extends com.google.common.collect.TransformedIterator<K, java.util.Map$Entry<K, V>>
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.google.common.collect.Maps$3
  super_class: com.google.common.collect.TransformedIterator
{
  private final com.google.common.base.Function val$function;
    descriptor: Lcom/google/common/base/Function;
    flags: (0x1012) ACC_PRIVATE, ACC_FINAL, ACC_SYNTHETIC

  void <init>(java.util.Iterator, com.google.common.base.Function);
    descriptor: (Ljava/util/Iterator;Lcom/google/common/base/Function;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=3, args_size=3
        start local 0 // com.google.common.collect.Maps$3 this
        start local 1 // java.util.Iterator $anonymous0
         0: .line 956
            aload 0 /* this */
            aload 2
            putfield com.google.common.collect.Maps$3.val$function:Lcom/google/common/base/Function;
            aload 0 /* this */
            aload 1 /* $anonymous0 */
            invokespecial com.google.common.collect.TransformedIterator.<init>:(Ljava/util/Iterator;)V
            return
        end local 1 // java.util.Iterator $anonymous0
        end local 0 // com.google.common.collect.Maps$3 this
      LocalVariableTable:
        Start  End  Slot         Name  Signature
            0    1     0         this  Lcom/google/common/collect/Maps$3;
            0    1     1  $anonymous0  Ljava/util/Iterator<+TK;>;
    MethodParameters:
              Name  Flags
      $anonymous0   
      val$function  final

  java.util.Map$Entry<K, V> transform(K);
    descriptor: (Ljava/lang/Object;)Ljava/util/Map$Entry;
    flags: (0x0000) 
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // com.google.common.collect.Maps$3 this
        start local 1 // java.lang.Object key
         0: .line 959
            aload 1 /* key */
            aload 0 /* this */
            getfield com.google.common.collect.Maps$3.val$function:Lcom/google/common/base/Function;
            aload 1 /* key */
            invokeinterface com.google.common.base.Function.apply:(Ljava/lang/Object;)Ljava/lang/Object;
            invokestatic com.google.common.collect.Maps.immutableEntry:(Ljava/lang/Object;Ljava/lang/Object;)Ljava/util/Map$Entry;
            areturn
        end local 1 // java.lang.Object key
        end local 0 // com.google.common.collect.Maps$3 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/Maps$3;
            0    1     1   key  TK;
    Signature: (TK;)Ljava/util/Map$Entry<TK;TV;>;
    MethodParameters:
      Name  Flags
      key   final

  java.lang.Object transform(java.lang.Object);
    descriptor: (Ljava/lang/Object;)Ljava/lang/Object;
    flags: (0x1040) ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=2, locals=2, args_size=2
         0: .line 1
            aload 0
            aload 1
            checkcast java.lang.Object
            invokevirtual com.google.common.collect.Maps$3.transform:(Ljava/lang/Object;)Ljava/util/Map$Entry;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature
}
Signature: Lcom/google/common/collect/TransformedIterator<TK;Ljava/util/Map$Entry<TK;TV;>;>;
SourceFile: "Maps.java"
EnclosingMethod: com.google.common.collect.Maps.asMapEntryIterator:(Ljava/util/Set;Lcom/google/common/base/Function;)Ljava/util/Iterator;
NestHost: com.google.common.collect.Maps
InnerClasses:
  com.google.common.collect.Maps$3
  public abstract Entry = java.util.Map$Entry of java.util.Map