http://netty.io/netty-all/: Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers and clients. (The Netty Project) 
final class io.netty.handler.codec.serialization.WeakReferenceMap<K, V> extends io.netty.handler.codec.serialization.ReferenceMap<K, V>
  minor version: 0
  major version: 59
  flags: flags: (0x0030) ACC_FINAL, ACC_SUPER
  this_class: io.netty.handler.codec.serialization.WeakReferenceMap
  super_class: io.netty.handler.codec.serialization.ReferenceMap
{
  void <init>(java.util.Map<K, java.lang.ref.Reference<V>>);
    descriptor: (Ljava/util/Map;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // io.netty.handler.codec.serialization.WeakReferenceMap this
        start local 1 // java.util.Map delegate
         0: .line 25
            aload 0 /* this */
            aload 1 /* delegate */
            invokespecial io.netty.handler.codec.serialization.ReferenceMap.<init>:(Ljava/util/Map;)V
         1: .line 26
            return
        end local 1 // java.util.Map delegate
        end local 0 // io.netty.handler.codec.serialization.WeakReferenceMap this
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0    2     0      this  Lio/netty/handler/codec/serialization/WeakReferenceMap<TK;TV;>;
            0    2     1  delegate  Ljava/util/Map<TK;Ljava/lang/ref/Reference<TV;>;>;
    Signature: (Ljava/util/Map<TK;Ljava/lang/ref/Reference<TV;>;>;)V
    MethodParameters:
          Name  Flags
      delegate  

  java.lang.ref.Reference<V> fold(V);
    descriptor: (Ljava/lang/Object;)Ljava/lang/ref/Reference;
    flags: (0x0000) 
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // io.netty.handler.codec.serialization.WeakReferenceMap this
        start local 1 // java.lang.Object value
         0: .line 30
            new java.lang.ref.WeakReference
            dup
            aload 1 /* value */
            invokespecial java.lang.ref.WeakReference.<init>:(Ljava/lang/Object;)V
            areturn
        end local 1 // java.lang.Object value
        end local 0 // io.netty.handler.codec.serialization.WeakReferenceMap this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0    1     0   this  Lio/netty/handler/codec/serialization/WeakReferenceMap<TK;TV;>;
            0    1     1  value  TV;
    Signature: (TV;)Ljava/lang/ref/Reference<TV;>;
    MethodParameters:
       Name  Flags
      value  
}
Signature: <K:Ljava/lang/Object;V:Ljava/lang/Object;>Lio/netty/handler/codec/serialization/ReferenceMap<TK;TV;>;
SourceFile: "WeakReferenceMap.java"