Custom deserializer compilation error

[alexxomka]

I have got a problem with creation custom deserializer like Optional
Error:

[INFO]    [ERROR] Errors in Mappers_RestWrapperMapperImpl.java'
[INFO]       [ERROR] Line 17: Type mismatch: cannot convert from RestWrapperDeserializer<Object> to JsonDeserializer<RestWrapper>

Wrapper class:

public class RestWrapper<T> {
    private T object;

    public RestWrapper() {
    }

    public RestWrapper(T object) {
        this.object = object;
    }

    //    @JsonTypeInfo(use = JsonTypeInfo.Id.CLASS)
    public T getObject() {
        return object;
    }

    public void setObject(T object) {
        this.object = object;
    }
}

Desrializer:

public final class RestWrapperDeserializer<T> extends JsonDeserializer<RestWrapper<T>> {

    public static <T> RestWrapperDeserializer<T> newInstance( JsonDeserializer<T> deserializer ) {
        return new RestWrapperDeserializer<T>( deserializer );
    }

    private final JsonDeserializer<T> deserializer;

    private RestWrapperDeserializer( JsonDeserializer<T> deserializer ) {
        if ( null == deserializer ) {
            throw new IllegalArgumentException( "deserializer can't be null" );
        }
        this.deserializer = deserializer;
    }

    @Override
    protected RestWrapper<T> deserializeNullValue( JsonReader reader, JsonDeserializationContext ctx, JsonDeserializerParameters params ) {
        reader.skipValue();
        return new RestWrapper<>();
    }

    @Override
    public RestWrapper<T> doDeserialize( JsonReader reader, JsonDeserializationContext ctx, JsonDeserializerParameters params ) {
        return new RestWrapper<>( deserializer.deserialize( reader, ctx, params ) );
    }
    @Override
    public void setBackReference( String referenceName, Object reference, RestWrapper<T> value, JsonDeserializationContext ctx ) {
        if ( null != value ) {
            deserializer.setBackReference( referenceName, reference, value.getObject(), ctx );
        }
    }
}

Configuration and initialization:

public static final RestWrapperMapper REST_WRAPPER_MAPPER = GWT.create(RestWrapperMapper.class);        
public interface RestWrapperMapper extends ObjectMapper<RestWrapper> {}

type(RestWrapper.class).serializer(RestWrapperSerializer.class).deserializer(RestWrapperDeserializer.class);