code: private static String getClassSignature(TypeElement element) throws IOException
      {
          Result sb = new Result();
          formalTypeParameters(sb, element.getTypeParameters());
          TypeMirror superclass = element.getSuperclass();
          // SuperclassSignature:
          //     ClassTypeSignature
          if (superclass != null)
          {
              classTypeSignature(sb, superclass);
          }
          // SuperinterfaceSignature:
          //    ClassTypeSignature
          for (TypeMirror intf : element.getInterfaces())
          {
              classTypeSignature(sb, intf);
          }
          return sb.toString();
      }
docs: ClassSignature:
  FormalTypeParametersopt SuperclassSignature SuperinterfaceSignature*
  
  <U:Ljava/lang/Integer;:Ljava/io/Serializable;>Lorg/vesalainen/bcc/Test;Ljava/lang/Cloneable;;
  
  @param clazz
  @return