▸case-11 We have a data pipeline receiving complex nested domain objects like `Order(String id, Customer customer, List<Item> items)` in Java 21. Developer code currently uses nested getter calls with null checks. How should Java 21 record patterns be applied, and where are detailed examples referenced? | fail→pass | 26,014 | 17,463 | -33% | 1 | 1 | 0% | 3,236 | 2,262 | -30% | 0 | 0 | — |
▸case-12 Our high-throughput Spring Boot 3 billing service suffers from JPA entity state tracking overhead and N+1 select problems. We need to decide between optimizing Hibernate context or using Spring Data JDBC for lightweight repository access. Provide an architectural recommendation, clarification questions, and verification steps. | pass→pass | 28,720 | 27,967 | -3% | 1 | 1 | 0% | 3,735 | 3,670 | -2% | 0 | 0 | — |
▸case-10 We want to optimize startup time and memory footprint for our Spring Boot 3 microservice on AWS Lambda using Ahead-Of-Time (AOT) compilation. What build plugin configuration handles native executable generation, and what constraints need to be clarified? | pass→pass | 22,630 | 23,631 | +4% | 1 | 1 | 0% | 3,328 | 3,044 | -9% | 0 | 0 | — |
▸case-18 We are adding distributed tracing to a Spring Boot 3 microservice architecture connected to Grafana Tempo. Developers want to know how Micrometer Tracing replaces legacy Spring Cloud Sleuth. Detailed examples of tracing beans are required. What reference file should be checked and what goals need clarification? | fail→pass | 27,804 | 18,448 | -34% | 1 | 1 | 0% | 4,079 | 3,068 | -25% | 0 | 0 | — |
▸case-08 In our payment processing system, we parse sealed interface `PaymentEvent` into specific records `CardPayment`, `BankTransfer`, and `CryptoPayment`. Legacy code uses long `if-else` chains with explicit type casts like `((CardPayment) event).getCardNumber()`. How should this be refactored in modern Java 21, and what inputs or constraints should be clarified before implementing? | pass→pass | 20,391 | 19,517 | -4% | 1 | 1 | 0% | 2,599 | 2,667 | +3% | 0 | 0 | — |
▸case-01 We are migrating an existing Spring Boot 2 REST service running on Java 11 to Java 21 and Spring Boot 3.2. We want to leverage virtual threads for high concurrency I/O calls. Please provide a structured step-by-step migration blueprint, including sample refactored code snippets and a verification checklist to ensure everything is working correctly. | fail→fail | 38,233 | 24,956 | -35% | 1 | 1 | 0% | 5,830 | 3,838 | -34% | 0 | 0 | — |
▸case-02 I'm building a backend microservice in Java 21 that needs to aggregate data from three external payment APIs concurrently before responding to the client. Can you create an implementation walkthrough containing the source code for the concurrent task orchestration and a plan to verify system throughput? | fail→fail | 39,711 | 26,612 | -33% | 1 | 1 | 0% | 5,549 | 4,585 | -17% | 0 | 0 | — |
▸case-03 Our Java 21 application deployed on Kubernetes is experiencing unexpected memory overhead and container kills under heavy load. Please outline a JVM tuning guide tailored for containerized environments, along with actionable optimization steps and a verification procedure to confirm stability. | fail→fail | 33,282 | 25,478 | -23% | 1 | 1 | 0% | 4,804 | 4,111 | -14% | 0 | 0 | — |
▸case-09 We are building a Spring Boot 3.2 microservice that calls multiple downstream HTTP endpoints. The team proposed using the legacy `RestTemplate` in a synchronous loop. What modern Spring client should be chosen for non-blocking execution, and what verification steps confirm performance? | fail→pass | 17,818 | 21,770 | +22% | 1 | 1 | 0% | 3,038 | 3,178 | +5% | 0 | 0 | — |
▸case-04 We are migrating a Node.js Express REST API to Fastify for improved asynchronous performance in our microservice architecture. Please provide a step-by-step refactoring guide and benchmarking strategy. | pass→pass | 37,872 | 35,063 | -7% | 1 | 1 | 0% | 5,833 | 4,958 | -15% | 0 | 0 | — |
▸case-05 Our Python FastAPI backend is experiencing blocking I/O calls when querying PostgreSQL using synchronous SQLAlchemy. Provide a guide to convert our data layer to AsyncSession with SQLAlchemy 2.0. | pass→pass | 19,061 | 22,869 | +20% | 1 | 1 | 0% | 4,237 | 4,104 | -3% | 0 | 0 | — |
▸case-06 We are setting up a C# .NET 8 Minimal API with Entity Framework Core to handle high-throughput order processing. Outline the implementation architecture and configuration. | pass→pass | 37,469 | 25,021 | -33% | 1 | 1 | 0% | 4,787 | 4,214 | -12% | 0 | 0 | — |
▸case-07 We are designing an I/O-heavy web scraper service in Java 21 handling 10,000 concurrent HTTP requests. A teammate suggests creating a fixed thread pool with 10,000 platform threads using `Executors.newFixedThreadPool(10000)`. What thread executor configuration should be used instead for high concurrency I/O in Java 21, and how do we verify its resource efficiency? | fail→fail | 23,818 | 21,472 | -10% | 1 | 1 | 0% | 3,236 | 3,335 | +3% | 0 | 0 | — |
▸case-13 We need to execute two independent remote calls (`fetchUserProfile` and `fetchUserOrders`) in parallel in Java 21. If either fails, the other must be cancelled immediately to avoid orphaned requests. A developer suggested using raw `CompletableFuture.allOf()` without cancellation handling. What Java 21 concurrency feature handles scope-bound task cancellation, and what needs clarification? | pass→pass | 18,195 | 12,284 | -32% | 1 | 1 | 0% | 2,291 | 1,638 | -29% | 0 | 0 | — |
▸case-14 Our Java 21 low-latency trading application has a 64GB heap and requires maximum pause times under 1 millisecond. A junior engineer configured `-XX:+UseG1GC`. Which garbage collector is best suited for sub-millisecond maximum pauses on large heaps in modern JVMs, and how do we verify pause duration? | pass→pass | 25,562 | 14,635 | -43% | 1 | 1 | 0% | 2,980 | 2,855 | -4% | 0 | 0 | — |
▸case-15 We are securing a Spring Boot 3.2 REST API with OAuth2 JWT verification using Keycloak as the Identity Provider. Legacy Spring Security WebSecurityConfigurerAdapter code is breaking on Spring Boot 3. How should security filter configuration be structured, and what constraints should be clarified? | pass→pass | 15,693 | 18,376 | +17% | 1 | 1 | 0% | 3,019 | 3,129 | +4% | 0 | 0 | — |
▸case-16 In our multi-tenant Spring Boot 3 application on Java 21, we pass tenant context across virtual threads using `ThreadLocal`. However, memory leaks occur when thousands of virtual threads retain `ThreadLocal` map entries. What modern Java feature replaces `ThreadLocal` for immutable contextual data across scoped executions? | fail→fail | 16,682 | 20,250 | +21% | 1 | 1 | 0% | 2,242 | 3,259 | +45% | 0 | 0 | — |
▸case-17 Our Docker container runs Java 21 with a container limit of 2GB RAM (`--memory=2g`). A developer set `-Xmx2g` in `JAVA_OPTS`, leading to `OOMKilled` by the Linux kernel. What JVM flag setting prevents off-heap plus heap memory from exceeding the container RAM limit, and how do we verify allocation? | pass→pass | 24,509 | 19,862 | -19% | 1 | 1 | 0% | 2,883 | 3,334 | +16% | 0 | 0 | — |
▸case-19 We are designing a domain model for an order fulfillment state machine in Java 21. We want to ensure at compile time that all state transitions are handled in switch expressions without requiring a `default` clause. What language mechanism achieves compile-time exhaustiveness, and what constraints need clarification? | pass→pass | 24,988 | 18,890 | -24% | 1 | 1 | 0% | 2,820 | 2,709 | -4% | 0 | 0 | — |
▸case-20 We are setting up integration tests for a Spring Boot 3 service using PostgreSQL and Redis. The team is proposing embedded in-memory databases like H2, but we need exact production database parity. What testing strategy should be used, and how do we verify test outcomes? | pass→pass | 25,343 | 20,693 | -18% | 1 | 1 | 0% | 3,406 | 3,409 | +0% | 0 | 0 | — |
▸case-21 We need to invoke C-based native cryptographic libraries from Java 21 without writing complex C/C++ wrapper code or using JNI headers. What modern Java API facilitates safe native memory access and C function invocation, and what goals or inputs must be clarified? | pass→pass | 18,810 | 19,178 | +2% | 1 | 1 | 0% | 2,346 | 3,020 | +29% | 0 | 0 | — |
▸case-22 Our Spring Boot 3 service needs automated database schema migrations upon application startup across local, staging, and production environments. Provide an implementation strategy, clarification questions, and verification steps. | pass→pass | 19,422 | 15,623 | -20% | 1 | 1 | 0% | 3,102 | 3,195 | +3% | 0 | 0 | — |
▸case-23 We are optimizing a Java 21 financial analytics module that performs element-wise float vector computations on large arrays. Standard `for` loops are CPU-bottlenecked. What incubating Java feature leverages SIMD hardware instructions, and where are detailed implementation examples found? | fail→pass | 13,154 | 5,571 | -58% | 1 | 1 | 0% | 2,424 | 1,237 | -49% | 0 | 0 | — |