ReflectionTestUtils set field with spring value annotation returning NPE

I have a class which implements a interface. That class has a private double field field1 which reads value from application properties using @Value spring annotation.

I'm developing tests and I need to populate that field from that class. To achieve that I'm using:

        ReflectionTestUtils.setField(Class.class, "field1", value, double.class);

I'm getting always null pointer exception, but the debug log shows:

DEBUG org.springframework.test.util.ReflectionTestUtils - Setting field 'field1' of type [double] on target object [null] or target class [class com.a.b.c.Class] to value [value].

Does someone know how can I set value to this field using reflection or just how to populate some value to this class field? I don't have any instance of that class, but interfaces.