+1. Continuous profiling should help figuring out the root cause of such issues. I have only used an in-house tool for Java for this so far, so I don't have a r

+1. Continuous profiling should help figuring out the root cause of such issues. I have only used an in-house tool for Java for this so far, so I don't have a recommendation for a specific one. But the linked one looks reasonable, and there might be other tools too. It might not even require continuous profiling. One alternative approach is to capture some minutes of profiling data after startup (when CPU usage looks good), and some minutes after the CPU spikes occur. Then compare those two and check for major differences.