Free S90-08A sample questions

Correct answers: Each service that performs a state change (`DebitSourceAccount`, `CreditDestinationAccount`) must expose a corresponding compensating operation (e.g., `UndoDebit`, `UndoCredit`).; A central orchestration engine must persist the state of the entire business activity in a State Repository.

Correct answer: Protocol Bridging and Asynchronous Queuing.

The core problem is the synchronous coupling between a fast REST service and a slow batch system. Asynchronous Queuing decouples the two, allowing the claims service to post a request and move on immediately, thus resolving the timeout. The Protocol Bridging pattern is then applied by the ESB to handle the translation from the message in the queue (e.g., JSON over JMS) to the required FTP file transfer, bridging the technology gap. sequenceDiagram participant C as Claims Service participant ESB participant M as Mainframe Note over C, M: Before (Synchronous Call) C->>+ESB: ProcessClaim(REST) ESB->>+M: GenerateFile(FTP) Note right of M: Takes 5+ minutes M-->>-ESB: File Ready ESB-->>-C: Response (Timeout Occurs) Note over C, M: After (Asynchronous Queuing) C->>ESB: SendClaim(JMS) ESB-->>C: Acknowledged ESB->>M: GenerateFile(FTP) Note right of M: Takes 5+ minutes M-->>ESB: File Ready

Correct answer: True

The fundamental purpose of the Policy Centralization pattern is to externalize policy logic from service implementations. This allows policies (such as security, auditing, or SLA monitoring) to be managed, updated, and applied consistently across multiple services without requiring changes to the services themselves, thus promoting loose coupling and agility.

Correct answer: Cross-Service Data Composition

Cross-Service Data Composition is the correct pattern. It involves designing a composition controller (or the 'Product' service itself) to retrieve data from both the 'Product' and 'Inventory' services at runtime and combine them into a single data structure for the consumer. This avoids replicating inventory data within the 'Product' service's database, thereby ensuring the data is always current.

Correct answer: The service will be difficult to reuse in different business processes because its logic is too coarse-grained.

Service Composability dictates that services should be designed as effective composition members. A large, coarse-grained service that combines multiple distinct business functions (payment, inventory, shipping) cannot be easily reused. For example, a different business process that only needs to check inventory cannot reuse this service without invoking the unwanted payment and shipping logic. Breaking it down into smaller, more granular services (e.g., Payment Service, Inventory Service) would promote composability and reuse.

Correct answer: State Deferral

The State Deferral pattern is specifically designed for this scenario. Before making the unreliable, long-running service call, the orchestration engine persists the current state of the process instance to a database (State Repository). It then makes the call asynchronously. When the response arrives (or a timeout occurs), a separate process retrieves the state and resumes the orchestration. This frees up the engine's active threads, preventing them from being blocked and thereby improving scalability and resilience.

Correct answer: Entity Service

Creating an Entity Service layer is the correct approach. An Entity Service is specifically designed to represent and manage a business entity and its corresponding data. By creating a set of Entity Services (e.g., Customer Service, Product Service) that are the sole gatekeepers to the legacy database, you encapsulate the data access logic. All other services must go through these Entity Services, which enforces loose coupling, standardizes data access, and provides a clear path for future modernization of the data layer.

Correct answer: Applying the Rules Centralization pattern by invoking an external Business Rules Engine.

The Rules Centralization pattern is the ideal solution. It involves externalizing the business rules into a dedicated Business Rules Engine (BRE). The orchestration service would pass the relevant data (like the credit score) to the BRE, which then returns a decision (e.g., 'Instant Approval'). This decouples the process flow from the business logic, allowing business analysts to update the rules in the BRE's repository without changing and redeploying the orchestration service code.

Correct answer: Concurrent Contracts

The Concurrent Contracts pattern allows a single service to support multiple, technologically distinct contracts. Each contract can specify a different communication protocol, data format, or security requirement, while all pointing to the same underlying service logic. This decouples the service's abstract interface from its physical implementation details, providing the required flexibility.

Correct answer: Enterprise Service Bus (as a compound pattern)

The scenario describes the classic implementation of the Enterprise Service Bus (ESB) as a compound design pattern. The ESB itself is an architectural style, but its implementation involves the composition of several granular patterns: Protocol Bridging (implied), Data Model Transformation, Content Enrichment, and Content-Based Routing. The described sequence is a textbook example of an ESB message flow.