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 abstract class io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionDecoder extends io.netty.handler.codec.MessageToMessageDecoder<io.netty.handler.codec.http.websocketx.WebSocketFrame>
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionDecoder
  super_class: io.netty.handler.codec.MessageToMessageDecoder
{
  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionDecoder this
         0: .line 24
            aload 0 /* this */
            invokespecial io.netty.handler.codec.MessageToMessageDecoder.<init>:()V
            return
        end local 0 // io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionDecoder this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lio/netty/handler/codec/http/websocketx/extensions/WebSocketExtensionDecoder;
}
Signature: Lio/netty/handler/codec/MessageToMessageDecoder<Lio/netty/handler/codec/http/websocketx/WebSocketFrame;>;
SourceFile: "WebSocketExtensionDecoder.java"