This article addresses troubleshooting CPU spikes in Java applications caused by two main issues: repeated Full Garbage Collections (GC) due to memory leaks and infinitely looping threads. It provides guidance on diagnosing these problems using tools like GCeasy and fastThread, helping users identify root causes and implement effective fixes.
The Dining Philosophers problem illustrates a classic issue in concurrent programming, resulting in a circular deadlock. Each thread holds a lock while waiting for another, leading to a cycle that prevents any thread from proceeding. Recovery from this deadlock requires restarting the JVM and re-engineering the code to avoid this pattern.
This content introduces a presentation on JVM Internals, summarizing key topics such as JVM Architecture, memory model, and Garbage Collection in just three slides. It emphasizes the clarity and conciseness of the information provided, making it accessible for users seeking to understand JVM fundamentals quickly.
Prolonged thread blocking in applications signals potential issues, affecting responsiveness. An example illustrates a thread remaining blocked due to another not releasing a lock, causing system unresponsiveness. The analogy to atherosclerosis highlights how blocked threads impede function, potentially leading to application failure. Key factors include deadlocks and unresponsive external services.
To diagnose JVM issues, capturing three thread dumps at 10-second intervals is recommended. An example highlighted a thread leak due to an Oracle JDBC Driver bug from 2011, leading to excessive thread creation. In this case, 1700 threads entered RUNNABLE state, emphasizing the importance of observing thread behaviors for potential problems.
In this training program, engineers will be equipped with necessary knowledge to optimize CPU, memory and response time.