https://github.com/cglib/cglib/cglib: cglib is a powerful, high performance and quality Code Generation Library, It is used to extend JAVA classes and implements interfaces at runtime. 
public interface net.sf.cglib.proxy.NoOp extends net.sf.cglib.proxy.Callback
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: net.sf.cglib.proxy.NoOp
  super_class: java.lang.Object
{
  public static final net.sf.cglib.proxy.NoOp INSTANCE;
    descriptor: Lnet/sf/cglib/proxy/NoOp;
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL

  static void <clinit>();
    descriptor: ()V
    flags: (0x0008) ACC_STATIC
    Code:
      stack=2, locals=0, args_size=0
         0: .line 27
            new net.sf.cglib.proxy.NoOp$1
            dup
            invokespecial net.sf.cglib.proxy.NoOp$1.<init>:()V
            putstatic net.sf.cglib.proxy.NoOp.INSTANCE:Lnet/sf/cglib/proxy/NoOp;
            return
      LocalVariableTable:
        Start  End  Slot  Name  Signature
}
SourceFile: "NoOp.java"
NestMembers:
  net.sf.cglib.proxy.NoOp$1
InnerClasses:
  net.sf.cglib.proxy.NoOp$1