'java.lang.ClassCastException class xxxxx cannot be cast to class io.micronaut.data.model.Page Micronaut data

Trying to implement the pagination with Micronaut data with MongoDB as below

@MongoRepository
public interface IDiscountRepository extends ReactorCrudRepository<Discount, ObjectId> , ReactorJpaSpecificationExecutor<Discount> {
    @NonNull
    Flux<Page<Discount>> findAll(@Nullable PredicateSpecification<Discount> spec, Pageable pageable);
}

service

public Flux<DiscountModel> find(DiscountFilterModel searchCriteria) {
        LOG.info("Find the discount");
        var test = Mono.from(iDiscountRepository.findAll(QueryBuilder(searchCriteria), Pageable.from(0, 2))).block();
        return iDiscountRepository.findAll(QueryBuilder(searchCriteria), Pageable.from(0,2)).map(item -> this.mapDiscountToModel(item.));
    }

Query builder

@Introspected
public record QueryBuilderSpecification() {
    public static PredicateSpecification<Discount> QueryBuilder(DiscountFilterModel discountFilterModel){
        PredicateSpecification<Discount> predicateSpecification = null;

        if (discountFilterModel.getId() != null){
            predicateSpecification = DiscountIdEquals(new ObjectId(discountFilterModel.getId()));
        }
        if (discountFilterModel.getDiscountCode() != null){
            predicateSpecification = DiscountCodeEquals(discountFilterModel.getDiscountCode());
        }
        return predicateSpecification;
    }
}

Predicate

public class DiscountSpecification {
    final static BeanIntrospection<Discount> introspection = BeanIntrospection.getIntrospection(Discount.class);
    static String[] discountProperty = introspection.getPropertyNames();

    public static PredicateSpecification<Discount> DiscountIdEquals(ObjectId DiscountId) {
        return (root, criteriaBuilder) -> criteriaBuilder.equal(root.get(discountProperty[0]), DiscountId);
    }

    public static PredicateSpecification<Discount> DiscountCodeEquals(String DiscountCode) {
        return (root, criteriaBuilder) -> criteriaBuilder.equal(root.get(discountProperty[1]), DiscountCode);
    }
}

Exception

java.lang.ClassCastException: class fete.bird.entities.Discount cannot be cast to class io.micronaut.data.model.Page (fete.bird.entities.Discount and io.micronaut.data.model.Page are in unnamed module of loader 'app')
    at fete.bird.service.DiscountService.find(DiscountService.java:30)
    at fete.bird.aggregate.query.GetDiscountsQuery$GetDiscountsQueryHandler.handler(GetDiscountsQuery.java:23)
    at fete.bird.aggregate.query.GetDiscountsQuery$GetDiscountsQueryHandler.handler(GetDiscountsQuery.java:15)
    at fete.bird.utils.ServiceBus.send(ServiceBus.java:27)
    at fete.bird.api.v1.controller.DiscountController.find(DiscountController.java:48)
    at fete.bird.api.v1.controller.$DiscountController$Definition$Intercepted.$$access$$find(Unknown Source)
    at fete.bird.api.v1.controller.$DiscountController$Definition$Exec.dispatch(Unknown Source)
    at io.micronaut.context.AbstractExecutableMethodsDefinition$DispatchedExecutableMethod.invoke(AbstractExecutableMethodsDefinition.java:378)
    at io.micronaut.aop.chain.MethodInterceptorChain.proceed(MethodInterceptorChain.java:128)
    at io.micronaut.validation.ValidatingInterceptor.intercept(ValidatingInterceptor.java:138)
    at io.micronaut.aop.chain.MethodInterceptorChain.proceed(MethodInterceptorChain.java:137)
    at fete.bird.api.v1.controller.$DiscountController$Definition$Intercepted.find(Unknown Source)
    at fete.bird.api.v1.controller.$DiscountController$Definition$Exec.dispatch(Unknown Source)
    at io.micronaut.context.AbstractExecutableMethodsDefinition$DispatchedExecutableMethod.invoke(AbstractExecutableMethodsDefinition.java:378)
    at io.micronaut.context.DefaultBeanContext$4.invoke(DefaultBeanContext.java:583)
    at io.micronaut.web.router.AbstractRouteMatch.execute(AbstractRouteMatch.java:303)
    at io.micronaut.web.router.RouteMatch.execute(RouteMatch.java:111)
    at io.micronaut.http.context.ServerRequestContext.with(ServerRequestContext.java:103)
    at io.micronaut.http.server.RouteExecutor.lambda$executeRoute$14(RouteExecutor.java:659)
    at reactor.core.publisher.FluxDeferContextual.subscribe(FluxDeferContextual.java:49)
    at reactor.core.publisher.Flux.subscribe(Flux.java:8469)
    at reactor.core.publisher.FluxFlatMap$FlatMapMain.onNext(FluxFlatMap.java:426)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onNext(ReactorSubscriber.java:57)
    at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2398)
    at reactor.core.publisher.FluxFlatMap$FlatMapMain.onSubscribe(FluxFlatMap.java:371)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onSubscribe(ReactorSubscriber.java:50)
    at reactor.core.publisher.FluxJust.subscribe(FluxJust.java:68)
    at reactor.core.publisher.Flux.subscribe(Flux.java:8469)
    at reactor.core.publisher.MonoFlatMapMany$FlatMapManyMain.onNext(MonoFlatMapMany.java:195)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onNext(ReactorSubscriber.java:57)
    at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:82)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onNext(ReactorSubscriber.java:57)
    at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.innerNext(FluxConcatMap.java:282)
    at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:863)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onNext(ReactorSubscriber.java:57)
    at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onNext(MonoPeekTerminal.java:180)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onNext(ReactorSubscriber.java:57)
    at reactor.core.publisher.FluxFilter$FilterSubscriber.onNext(FluxFilter.java:113)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onNext(ReactorSubscriber.java:57)
    at reactor.core.publisher.FluxDefaultIfEmpty$DefaultIfEmptySubscriber.onNext(FluxDefaultIfEmpty.java:101)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onNext(ReactorSubscriber.java:57)
    at reactor.core.publisher.FluxHide$SuppressFuseableSubscriber.onNext(FluxHide.java:137)
    at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2398)
    at reactor.core.publisher.FluxHide$SuppressFuseableSubscriber.request(FluxHide.java:152)
    at reactor.core.publisher.FluxDefaultIfEmpty$DefaultIfEmptySubscriber.request(FluxDefaultIfEmpty.java:77)
    at reactor.core.publisher.FluxFilter$FilterSubscriber.request(FluxFilter.java:186)
    at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.request(MonoPeekTerminal.java:139)
    at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2194)
    at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onSubscribe(Operators.java:2068)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onSubscribe(ReactorSubscriber.java:50)
    at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onSubscribe(MonoPeekTerminal.java:152)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onSubscribe(ReactorSubscriber.java:50)
    at reactor.core.publisher.FluxFilter$FilterSubscriber.onSubscribe(FluxFilter.java:85)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onSubscribe(ReactorSubscriber.java:50)
    at reactor.core.publisher.FluxDefaultIfEmpty$DefaultIfEmptySubscriber.onSubscribe(FluxDefaultIfEmpty.java:91)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onSubscribe(ReactorSubscriber.java:50)
    at reactor.core.publisher.FluxHide$SuppressFuseableSubscriber.onSubscribe(FluxHide.java:122)
    at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:55)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4400)
    at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:451)
    at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onSubscribe(FluxConcatMap.java:219)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onSubscribe(ReactorSubscriber.java:50)
    at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:165)
    at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:87)
    at reactor.core.publisher.InternalFluxOperator.subscribe(InternalFluxOperator.java:62)
    at reactor.core.publisher.FluxDefer.subscribe(FluxDefer.java:54)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4400)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:82)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onComplete(ReactorSubscriber.java:71)
    at reactor.core.publisher.MonoFlatMap$FlatMapMain.onComplete(MonoFlatMap.java:181)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onComplete(ReactorSubscriber.java:71)
    at reactor.core.publisher.MonoNext$NextSubscriber.onComplete(MonoNext.java:102)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onComplete(ReactorSubscriber.java:71)
    at reactor.core.publisher.FluxFlatMap$FlatMapMain.checkTerminated(FluxFlatMap.java:846)
    at reactor.core.publisher.FluxFlatMap$FlatMapMain.drainLoop(FluxFlatMap.java:608)
    at reactor.core.publisher.FluxFlatMap$FlatMapMain.drain(FluxFlatMap.java:588)
    at reactor.core.publisher.FluxFlatMap$FlatMapMain.onComplete(FluxFlatMap.java:465)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onComplete(ReactorSubscriber.java:71)
    at reactor.core.publisher.FluxIterable$IterableSubscription.slowPath(FluxIterable.java:294)
    at reactor.core.publisher.FluxIterable$IterableSubscription.request(FluxIterable.java:230)
    at reactor.core.publisher.FluxFlatMap$FlatMapMain.onSubscribe(FluxFlatMap.java:371)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onSubscribe(ReactorSubscriber.java:50)
    at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:165)
    at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:87)
    at reactor.core.publisher.Flux.subscribe(Flux.java:8469)
    at io.micronaut.tracing.brave.instrument.http.HttpServerTracingPublisher.subscribe(HttpServerTracingPublisher.java:85)
    at reactor.core.publisher.FluxSource.subscribe(FluxSource.java:67)
    at reactor.core.publisher.Flux.subscribe(Flux.java:8469)
    at io.micronaut.http.server.netty.RoutingInBoundHandler.handleRouteMatch(RoutingInBoundHandler.java:586)
    at io.micronaut.http.server.netty.RoutingInBoundHandler.channelRead0(RoutingInBoundHandler.java:449)
    at io.micronaut.http.server.netty.RoutingInBoundHandler.channelRead0(RoutingInBoundHandler.java:144)
    at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:99)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

Not able to cast the class, not sure how to fix this one.

Reference - https://micronaut-projects.github.io/micronaut-data/latest/guide/#pagination

Solution 1:^[1]

This is fixed in the latest version of Micronaut Data 3.4 and will be included in Micronaut 3.5 release.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution	Source
Solution 1	Denis

'java.lang.ClassCastException class xxxxx cannot be cast to class io.micronaut.data.model.Page Micronaut data

Solution 1:[1]

Sources

Related Questions

Solution 1:^[1]