public void config(Class<?> clazz, SerializerFeature feature, boolean value) {
        ObjectSerializer serializer = getObjectWriter(clazz, false);
        
        if (serializer == null) {
            SerializeBeanInfo beanInfo = TypeUtils.buildBeanInfo(clazz, null, propertyNamingStrategy);
            
            if (value) {
                beanInfo.features |= feature.mask;
            } else {
                beanInfo.features &= ~feature.mask;
            }
            
            serializer = this.createJavaBeanSerializer(beanInfo);
            
            put(clazz, serializer);
            return;
        }

        if (serializer instanceof JavaBeanSerializer) {
            JavaBeanSerializer javaBeanSerializer = (JavaBeanSerializer) serializer;
            SerializeBeanInfo beanInfo = javaBeanSerializer.beanInfo;
            
            int originalFeaturs = beanInfo.features;
            if (value) {
                beanInfo.features |= feature.mask;
            } else {
                beanInfo.features &= ~feature.mask;
            }
            
            if (originalFeaturs == beanInfo.features) {
                return;
            }
            
            Class<?> serializerClass = serializer.getClass();
            if (serializerClass != JavaBeanSerializer.class) {
                ObjectSerializer newSerializer = this.createJavaBeanSerializer(beanInfo);
                this.put(clazz, newSerializer);
            }
        }
    }
class level serializer feature config
@since 1.2.12
src/main/java/com/alibaba/fastjson/serializer/SerializeConfig.java