code: public static void setField(final Object object, final String fieldName, final Object fieldNewValue) {
      try {
        traverseClassHierarchy(object.getClass(), NoSuchFieldException.class, new InsideTraversal<Void>() {
          @Override
          public Void run(Class<?> traversalClass) throws Exception {
            Field field = traversalClass.getDeclaredField(fieldName);
            field.setAccessible(true);
            field.set(object, fieldNewValue);
            return null;
          }
        });
      } catch (Exception e) {
        throw new RuntimeException(e);
      }
    }
docs: Reflectively set the value of a field.
  
  @param object Target object.
  @param fieldName The field name.
  @param fieldNewValue New value.