code: protected static Object getParamArg(Class cl)
      {
          if (!cl.isPrimitive())
              return null;
          else if (boolean.class.equals(cl))
              return Boolean.FALSE;
          else if (byte.class.equals(cl))
              return Byte.valueOf((byte) 0);
          else if (short.class.equals(cl))
              return Short.valueOf((short) 0);
          else if (char.class.equals(cl))
              return Character.valueOf((char) 0);
          else if (int.class.equals(cl))
              return Integer.valueOf(0);
          else if (long.class.equals(cl))
              return Long.valueOf(0);
          else if (float.class.equals(cl))
              return Double.valueOf(0);
          else if (double.class.equals(cl))
              return Double.valueOf(0);
          else
              throw new UnsupportedOperationException();
      }
docs: Creates a map of the classes fields.