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) 
public class io.netty.example.uptime.UptimeClientHandler extends io.netty.channel.SimpleChannelInboundHandler<java.lang.Object>
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: io.netty.example.uptime.UptimeClientHandler
  super_class: io.netty.channel.SimpleChannelInboundHandler
{
  long startTime;
    descriptor: J
    flags: (0x0000) 

  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // io.netty.example.uptime.UptimeClientHandler this
         0: .line 31
            aload 0 /* this */
            invokespecial io.netty.channel.SimpleChannelInboundHandler.<init>:()V
         1: .line 33
            aload 0 /* this */
            ldc -1
            putfield io.netty.example.uptime.UptimeClientHandler.startTime:J
         2: .line 31
            return
        end local 0 // io.netty.example.uptime.UptimeClientHandler this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lio/netty/example/uptime/UptimeClientHandler;

  public void channelActive(io.netty.channel.ChannelHandlerContext);
    descriptor: (Lio/netty/channel/ChannelHandlerContext;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=4, locals=2, args_size=2
        start local 0 // io.netty.example.uptime.UptimeClientHandler this
        start local 1 // io.netty.channel.ChannelHandlerContext ctx
         0: .line 37
            aload 0 /* this */
            getfield io.netty.example.uptime.UptimeClientHandler.startTime:J
            lconst_0
            lcmp
            ifge 2
         1: .line 38
            aload 0 /* this */
            invokestatic java.lang.System.currentTimeMillis:()J
            putfield io.netty.example.uptime.UptimeClientHandler.startTime:J
         2: .line 40
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            new java.lang.StringBuilder
            dup
            ldc "Connected to: "
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            aload 1 /* ctx */
            invokeinterface io.netty.channel.ChannelHandlerContext.channel:()Lio/netty/channel/Channel;
            invokeinterface io.netty.channel.Channel.remoteAddress:()Ljava/net/SocketAddress;
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/Object;)Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            invokevirtual io.netty.example.uptime.UptimeClientHandler.println:(Ljava/lang/String;)V
         3: .line 41
            return
        end local 1 // io.netty.channel.ChannelHandlerContext ctx
        end local 0 // io.netty.example.uptime.UptimeClientHandler this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    4     0  this  Lio/netty/example/uptime/UptimeClientHandler;
            0    4     1   ctx  Lio/netty/channel/ChannelHandlerContext;
    MethodParameters:
      Name  Flags
      ctx   

  public void channelRead0(io.netty.channel.ChannelHandlerContext, java.lang.Object);
    descriptor: (Lio/netty/channel/ChannelHandlerContext;Ljava/lang/Object;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=0, locals=3, args_size=3
        start local 0 // io.netty.example.uptime.UptimeClientHandler this
        start local 1 // io.netty.channel.ChannelHandlerContext ctx
        start local 2 // java.lang.Object msg
         0: .line 46
            return
        end local 2 // java.lang.Object msg
        end local 1 // io.netty.channel.ChannelHandlerContext ctx
        end local 0 // io.netty.example.uptime.UptimeClientHandler this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lio/netty/example/uptime/UptimeClientHandler;
            0    1     1   ctx  Lio/netty/channel/ChannelHandlerContext;
            0    1     2   msg  Ljava/lang/Object;
    Exceptions:
      throws java.lang.Exception
    MethodParameters:
      Name  Flags
      ctx   
      msg   

  public void userEventTriggered(io.netty.channel.ChannelHandlerContext, java.lang.Object);
    descriptor: (Lio/netty/channel/ChannelHandlerContext;Ljava/lang/Object;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=4, args_size=3
        start local 0 // io.netty.example.uptime.UptimeClientHandler this
        start local 1 // io.netty.channel.ChannelHandlerContext ctx
        start local 2 // java.lang.Object evt
         0: .line 50
            aload 2 /* evt */
            instanceof io.netty.handler.timeout.IdleStateEvent
            ifne 2
         1: .line 51
            return
         2: .line 54
      StackMap locals:
      StackMap stack:
            aload 2 /* evt */
            checkcast io.netty.handler.timeout.IdleStateEvent
            astore 3 /* e */
        start local 3 // io.netty.handler.timeout.IdleStateEvent e
         3: .line 55
            aload 3 /* e */
            invokevirtual io.netty.handler.timeout.IdleStateEvent.state:()Lio/netty/handler/timeout/IdleState;
            getstatic io.netty.handler.timeout.IdleState.READER_IDLE:Lio/netty/handler/timeout/IdleState;
            if_acmpne 6
         4: .line 57
            aload 0 /* this */
            ldc "Disconnecting due to no inbound traffic"
            invokevirtual io.netty.example.uptime.UptimeClientHandler.println:(Ljava/lang/String;)V
         5: .line 58
            aload 1 /* ctx */
            invokeinterface io.netty.channel.ChannelHandlerContext.close:()Lio/netty/channel/ChannelFuture;
            pop
         6: .line 60
      StackMap locals: io.netty.handler.timeout.IdleStateEvent
      StackMap stack:
            return
        end local 3 // io.netty.handler.timeout.IdleStateEvent e
        end local 2 // java.lang.Object evt
        end local 1 // io.netty.channel.ChannelHandlerContext ctx
        end local 0 // io.netty.example.uptime.UptimeClientHandler this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    7     0  this  Lio/netty/example/uptime/UptimeClientHandler;
            0    7     1   ctx  Lio/netty/channel/ChannelHandlerContext;
            0    7     2   evt  Ljava/lang/Object;
            3    7     3     e  Lio/netty/handler/timeout/IdleStateEvent;
    MethodParameters:
      Name  Flags
      ctx   
      evt   

  public void channelInactive(io.netty.channel.ChannelHandlerContext);
    descriptor: (Lio/netty/channel/ChannelHandlerContext;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=4, locals=2, args_size=2
        start local 0 // io.netty.example.uptime.UptimeClientHandler this
        start local 1 // io.netty.channel.ChannelHandlerContext ctx
         0: .line 64
            aload 0 /* this */
            new java.lang.StringBuilder
            dup
            ldc "Disconnected from: "
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            aload 1 /* ctx */
            invokeinterface io.netty.channel.ChannelHandlerContext.channel:()Lio/netty/channel/Channel;
            invokeinterface io.netty.channel.Channel.remoteAddress:()Ljava/net/SocketAddress;
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/Object;)Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            invokevirtual io.netty.example.uptime.UptimeClientHandler.println:(Ljava/lang/String;)V
         1: .line 65
            return
        end local 1 // io.netty.channel.ChannelHandlerContext ctx
        end local 0 // io.netty.example.uptime.UptimeClientHandler this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lio/netty/example/uptime/UptimeClientHandler;
            0    2     1   ctx  Lio/netty/channel/ChannelHandlerContext;
    MethodParameters:
      Name  Flags
      ctx   final

  public void channelUnregistered(io.netty.channel.ChannelHandlerContext);
    descriptor: (Lio/netty/channel/ChannelHandlerContext;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=5, locals=2, args_size=2
        start local 0 // io.netty.example.uptime.UptimeClientHandler this
        start local 1 // io.netty.channel.ChannelHandlerContext ctx
         0: .line 69
            aload 0 /* this */
            new java.lang.StringBuilder
            dup
            ldc "Sleeping for: "
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            getstatic io.netty.example.uptime.UptimeClient.RECONNECT_DELAY:I
            invokevirtual java.lang.StringBuilder.append:(I)Ljava/lang/StringBuilder;
            bipush 115
            invokevirtual java.lang.StringBuilder.append:(C)Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            invokevirtual io.netty.example.uptime.UptimeClientHandler.println:(Ljava/lang/String;)V
         1: .line 71
            aload 1 /* ctx */
            invokeinterface io.netty.channel.ChannelHandlerContext.channel:()Lio/netty/channel/Channel;
            invokeinterface io.netty.channel.Channel.eventLoop:()Lio/netty/channel/EventLoop;
            new io.netty.example.uptime.UptimeClientHandler$1
            dup
            aload 0 /* this */
            invokespecial io.netty.example.uptime.UptimeClientHandler$1.<init>:(Lio/netty/example/uptime/UptimeClientHandler;)V
         2: .line 77
            getstatic io.netty.example.uptime.UptimeClient.RECONNECT_DELAY:I
            i2l
            getstatic java.util.concurrent.TimeUnit.SECONDS:Ljava/util/concurrent/TimeUnit;
         3: .line 71
            invokeinterface io.netty.channel.EventLoop.schedule:(Ljava/lang/Runnable;JLjava/util/concurrent/TimeUnit;)Lio/netty/util/concurrent/ScheduledFuture;
            pop
         4: .line 78
            return
        end local 1 // io.netty.channel.ChannelHandlerContext ctx
        end local 0 // io.netty.example.uptime.UptimeClientHandler this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    5     0  this  Lio/netty/example/uptime/UptimeClientHandler;
            0    5     1   ctx  Lio/netty/channel/ChannelHandlerContext;
    Exceptions:
      throws java.lang.Exception
    MethodParameters:
      Name  Flags
      ctx   final

  public void exceptionCaught(io.netty.channel.ChannelHandlerContext, java.lang.Throwable);
    descriptor: (Lio/netty/channel/ChannelHandlerContext;Ljava/lang/Throwable;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=3, args_size=3
        start local 0 // io.netty.example.uptime.UptimeClientHandler this
        start local 1 // io.netty.channel.ChannelHandlerContext ctx
        start local 2 // java.lang.Throwable cause
         0: .line 82
            aload 2 /* cause */
            invokevirtual java.lang.Throwable.printStackTrace:()V
         1: .line 83
            aload 1 /* ctx */
            invokeinterface io.netty.channel.ChannelHandlerContext.close:()Lio/netty/channel/ChannelFuture;
            pop
         2: .line 84
            return
        end local 2 // java.lang.Throwable cause
        end local 1 // io.netty.channel.ChannelHandlerContext ctx
        end local 0 // io.netty.example.uptime.UptimeClientHandler this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0    3     0   this  Lio/netty/example/uptime/UptimeClientHandler;
            0    3     1    ctx  Lio/netty/channel/ChannelHandlerContext;
            0    3     2  cause  Ljava/lang/Throwable;
    MethodParameters:
       Name  Flags
      ctx    
      cause  

  void println(java.lang.String);
    descriptor: (Ljava/lang/String;)V
    flags: (0x0000) 
    Code:
      stack=9, locals=2, args_size=2
        start local 0 // io.netty.example.uptime.UptimeClientHandler this
        start local 1 // java.lang.String msg
         0: .line 87
            aload 0 /* this */
            getfield io.netty.example.uptime.UptimeClientHandler.startTime:J
            lconst_0
            lcmp
            ifge 3
         1: .line 88
            getstatic java.lang.System.err:Ljava/io/PrintStream;
            ldc "[SERVER IS DOWN] %s%n"
            iconst_1
            anewarray java.lang.Object
            dup
            iconst_0
            aload 1 /* msg */
            aastore
            invokevirtual java.io.PrintStream.format:(Ljava/lang/String;[Ljava/lang/Object;)Ljava/io/PrintStream;
            pop
         2: .line 89
            goto 4
         3: .line 90
      StackMap locals:
      StackMap stack:
            getstatic java.lang.System.err:Ljava/io/PrintStream;
            ldc "[UPTIME: %5ds] %s%n"
            iconst_2
            anewarray java.lang.Object
            dup
            iconst_0
            invokestatic java.lang.System.currentTimeMillis:()J
            aload 0 /* this */
            getfield io.netty.example.uptime.UptimeClientHandler.startTime:J
            lsub
            ldc 1000
            ldiv
            invokestatic java.lang.Long.valueOf:(J)Ljava/lang/Long;
            aastore
            dup
            iconst_1
            aload 1 /* msg */
            aastore
            invokevirtual java.io.PrintStream.format:(Ljava/lang/String;[Ljava/lang/Object;)Ljava/io/PrintStream;
            pop
         4: .line 92
      StackMap locals:
      StackMap stack:
            return
        end local 1 // java.lang.String msg
        end local 0 // io.netty.example.uptime.UptimeClientHandler this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    5     0  this  Lio/netty/example/uptime/UptimeClientHandler;
            0    5     1   msg  Ljava/lang/String;
    MethodParameters:
      Name  Flags
      msg   
}
Signature: Lio/netty/channel/SimpleChannelInboundHandler<Ljava/lang/Object;>;
SourceFile: "UptimeClientHandler.java"
NestMembers:
  io.netty.example.uptime.UptimeClientHandler$1
InnerClasses:
  public abstract Sharable = io.netty.channel.ChannelHandler$Sharable of io.netty.channel.ChannelHandler
  io.netty.example.uptime.UptimeClientHandler$1
    RuntimeVisibleAnnotations: 
      io.netty.channel.ChannelHandler$Sharable()