What methods will you use to solve the request processing delay problem in the service?

To solve the problem of request processing delay in a service, several approaches can be used:

• Profiling and monitoring: first identify bottlenecks using profiling tools (e.g., Java Flight Recorder, VisualVM).
• Asynchronous processing: use asynchronous calls, CompletableFuture, message queues (Kafka, RabbitMQ) to offload synchronous operations.
• Caching: implement caching of frequently requested data (e.g., Redis or built-in cache in the application).
• Database query optimization: check and optimize SQL queries, add indexes, use prepared statements.
• Thread pool: configure an optimal number of threads for request processing to avoid blocking and overload.
• Load balancing: use load balancers and service scaling (horizontal or vertical).

Example of asynchronous processing with CompletableFuture:

CompletableFuture.supplyAsync(() -> {
    // Long operation
    return fetchDataFromDB();
}).thenAccept(data -> {
    processData(data);
});