docs: public String getNotNullTrueStringRep() {
      try {
        String rep = "";
        String joiner = "\n";
        Field[] f = this.getClass().getFields();
        for (Field ff : f) {
  
          String name = ff.getName();
          Class<?> type = ff.getType();
  
          if (type.equals(Boolean.class) || type.equals(boolean.class)) {
            boolean val = ff.getBoolean(this);
            if (val == true)
              rep += joiner + name + "=" + val;
          } else if (type.equals(String.class)) {
            String val = (String) ff.get(this);
            if (val != null)
              rep += joiner + name + "=" + val;
          } else if (type.equals(Double.class)) {
            Double val = (Double) ff.get(this);
            rep += joiner + name + "=" + val;
          } else if (type.equals(double.class)) {
            double val = ff.getDouble(this);
            rep += joiner + name + "=" + val;
          } else if (type.equals(Integer.class)) {
            Integer val = (Integer) ff.get(this);
            rep += joiner + name + "=" + val;
          } else if (type.equals(int.class)) {
            int val = ff.getInt(this);
            rep += joiner + name + "=" + val;
          } else if (type.equals(Float.class)) {
            Float val = (Float) ff.get(this);
            rep += joiner + name + "=" + val;
          } else if (type.equals(float.class)) {
            float val = ff.getFloat(this);
            rep += joiner + name + "=" + val;
          } else if (type.equals(Byte.class)) {
            Byte val = (Byte) ff.get(this);
            rep += joiner + name + "=" + val;
          } else if (type.equals(byte.class)) {
            byte val = ff.getByte(this);
            rep += joiner + name + "=" + val;
          } else if (type.equals(char.class)) {
            char val = ff.getChar(this);
            rep += joiner + name + "=" + val;
          } else if (type.equals(Long.class)) {
            Long val = (Long) ff.get(this);
            rep += joiner + name + "=" + val;
          } else if (type.equals(long.class)) {
            long val = ff.getLong(this);
            rep += joiner + name + "=" + val;
          }
  
        }
        return rep;
      } catch (Exception e) {
        e.printStackTrace();
      }
      return null;
    }