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) 
class io.netty.resolver.dns.DnsNameResolver$3 implements io.netty.channel.ChannelFutureListener
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: io.netty.resolver.dns.DnsNameResolver$3
  super_class: java.lang.Object
{
  final io.netty.resolver.dns.DnsNameResolver this$0;
    descriptor: Lio/netty/resolver/dns/DnsNameResolver;
    flags: (0x1010) ACC_FINAL, ACC_SYNTHETIC

  private final io.netty.resolver.dns.DnsCache val$resolveCache;
    descriptor: Lio/netty/resolver/dns/DnsCache;
    flags: (0x1012) ACC_PRIVATE, ACC_FINAL, ACC_SYNTHETIC

  void <init>(io.netty.resolver.dns.DnsNameResolver, io.netty.resolver.dns.DnsCache);
    descriptor: (Lio/netty/resolver/dns/DnsNameResolver;Lio/netty/resolver/dns/DnsCache;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=3, args_size=3
        start local 0 // io.netty.resolver.dns.DnsNameResolver$3 this
         0: .line 307
            aload 0 /* this */
            aload 1
            putfield io.netty.resolver.dns.DnsNameResolver$3.this$0:Lio/netty/resolver/dns/DnsNameResolver;
            aload 0 /* this */
            aload 2
            putfield io.netty.resolver.dns.DnsNameResolver$3.val$resolveCache:Lio/netty/resolver/dns/DnsCache;
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // io.netty.resolver.dns.DnsNameResolver$3 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lio/netty/resolver/dns/DnsNameResolver$3;
    MethodParameters:
                  Name  Flags
      this$0            final
      val$resolveCache  final

  public void operationComplete(io.netty.channel.ChannelFuture);
    descriptor: (Lio/netty/channel/ChannelFuture;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=2, args_size=2
        start local 0 // io.netty.resolver.dns.DnsNameResolver$3 this
        start local 1 // io.netty.channel.ChannelFuture future
         0: .line 310
            aload 0 /* this */
            getfield io.netty.resolver.dns.DnsNameResolver$3.val$resolveCache:Lio/netty/resolver/dns/DnsCache;
            invokeinterface io.netty.resolver.dns.DnsCache.clear:()V
         1: .line 311
            return
        end local 1 // io.netty.channel.ChannelFuture future
        end local 0 // io.netty.resolver.dns.DnsNameResolver$3 this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0    2     0    this  Lio/netty/resolver/dns/DnsNameResolver$3;
            0    2     1  future  Lio/netty/channel/ChannelFuture;
    Exceptions:
      throws java.lang.Exception
    MethodParameters:
        Name  Flags
      future  

  public void operationComplete(io.netty.util.concurrent.Future);
    descriptor: (Lio/netty/util/concurrent/Future;)V
    flags: (0x1041) ACC_PUBLIC, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=2, locals=2, args_size=2
         0: .line 1
            aload 0
            aload 1
            checkcast io.netty.channel.ChannelFuture
            invokevirtual io.netty.resolver.dns.DnsNameResolver$3.operationComplete:(Lio/netty/channel/ChannelFuture;)V
            return
      LocalVariableTable:
        Start  End  Slot  Name  Signature
    Exceptions:
      throws java.lang.Exception
}
SourceFile: "DnsNameResolver.java"
EnclosingMethod: io.netty.resolver.dns.DnsNameResolver.<init>:(Lio/netty/channel/EventLoop;Lio/netty/channel/ChannelFactory;Lio/netty/resolver/dns/DnsCache;Lio/netty/resolver/dns/DnsCache;Lio/netty/resolver/dns/DnsQueryLifecycleObserverFactory;JLio/netty/resolver/ResolvedAddressTypes;ZIZIZLio/netty/resolver/HostsFileEntriesResolver;Lio/netty/resolver/dns/DnsServerAddressStreamProvider;[Ljava/lang/String;IZ)V
NestHost: io.netty.resolver.dns.DnsNameResolver
InnerClasses:
  io.netty.resolver.dns.DnsNameResolver$3