JVM Memory Regions
In a nutshell, the JVM (Java Virtual Machine) has the following memory regions: Inspired from
Types of OutOfMemoryErrors
Understanding different types of OutOfMemoryErrors is crucial for effective JVM memory management. Here are the main types:
1. OutOfMemoryError: Java Heap Space
Occurs when more objects are created in the 'Heap' (i.e., Young and Old) region than the allocated memory limit (i.e., '-Xmx').
Common Causes:
- Increase in Traffic Volume
- Memory Leak due to Buggy Code
2. OutOfMemoryError: GC Overhead Limit Exceeded
Thrown when the Java process spends more than 98% of its time doing garbage collection and recovering less than 2% of the heap for five consecutive garbage collections.
Common Causes:
- Increase in Traffic Volume
- Memory Leak due to Buggy Code
3. OutOfMemoryError: Requested Array Size Exceeds VM Limit
Occurs when trying to create an array larger than the maximum size allowed by the JVM.
4. OutOfMemoryError: Metaspace
Thrown when the Metaspace region is filled with more class definitions and method definitions than the allocated limit (i.e., '-XX:MaxMetaspaceSize').
Common Causes:
- Creating large number of dynamic classes
- Loading large number of classes
- Loading large number of class loaders
5. OutOfMemoryError: Meta Space
Similar to Metaspace error, but for Java versions before Java 8.
Common Causes:
- Creating large number of dynamic classes
- Loading large number of classes
- Loading large number of class loaders
6. OutOfMemoryError: Unable to Create New Native Threads
Occurs when a large number of threads are created in the native memory region, exceeding the available RAM capacity.
Common Causes:
- Thread Leak due to Buggy Code
- Lack of RAM capacity
- More processes in Memory
- Kernel Limit exceeded
7. OutOfMemoryError: Direct Buffer Memory
Thrown when too many objects are created in the direct buffer region, exceeding the allocated limit (i.e., '-XX:MaxDirectMemorySize').
Common Causes:
- Memory Leak due to Buggy code
- High Rate of Allocation
- Switching from Spring RestTemplate to WebClient
8. OutOfMemoryError: Kill Process or Sacrifice Child
Occurs when there's a lack of RAM capacity in the container/device, causing the kernel to terminate memory-consuming processes.
Common Causes:
- More processes in the device
- Initial and Max Heap size set to different values
- Native Memory region growing
9. OutOfMemoryError: Reason Stack Trace with Native Method
Happens when the JVM can't allocate sufficient memory for the execution stack of a thread containing native method invocations.
Common Causes:
- Heavy Usage of Native Methods
- Recursive Native Method Calls