Java service. Response time has increased, some requests are processed for several seconds. What will you look at first? At least 4 points.

When increasing the response time of a Java service and experiencing long processing of some requests, you should primarily check:

1. Database issues: slow queries, locks, lack of indexes, increasing query execution times.
2. GC (Garbage Collector) load: frequent or long garbage collection pauses can slow down processing.
3. Thread and lock issues: possible resource contention, deadlocks, or exhaustion of the thread pool.
4. External dependencies: delays in calls to other services, APIs, or resources.

Additionally, it is advisable to review logs, CPU and memory metrics, and profile the application to identify bottlenecks.