Because Meta Programming must be easy.

Setting Values

Setting value of a static field:
Class clazz;
new Mirror().on(clazz).set().field("fieldName").withValue(value);
Setting value of an instance field:
Object target;
new Mirror().on(target).set().field("fieldName").withValue(value);
You can also pass a java.lang.reflect.Field instead of fieldName String: Setting value of a static field:
Field aField;
Class clazz;
new Mirror().on(clazz).set().field(aField).withValue(value);