If the application worked fine, but errors OutOfMemoryError started when the load increased to 15k RPS, what is the plan of action?

When encountering an OutOfMemoryError as load increases to 15k RPS, a systematic approach is necessary:

1. Collect and analyze logs and metrics — identify when and where the error occurs, which objects occupy memory.
2. Perform a heap dump and analyze it using tools (e.g., VisualVM, Eclipse MAT) to detect memory leaks or excessive consumption.
3. Check JVM settings — possibly increase heap size or configure garbage collection.
4. Optimize code — identify objects that live long or are not released, fix leaks.
5. Conduct load testing with profiling — to understand how the application behaves under load.
6. Consider scaling — horizontal (adding instances) or vertical (increasing resources).

Example action plan:

- Collect heap dump during error
- Analyze memory leaks
- Optimize problematic code sections
- Configure JVM (heap size, GC)
- Repeat load testing
- Implement monitoring for early problem detection