shadowapi/src/main/java/org/robolectric/util/ReflectionHelpers.java
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);
    }
  }
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);
    }
  }
Reflectively set the value of a field.

@param object Target object.
@param fieldName The field name.
@param fieldNewValue New value.