Shenandoah is an open-source garbage collector (GC) that was introduced in JDK 12 as an experimental feature. It aims to reduce GC pause times and improve the overall throughput of applications, particularly those with large heaps.

When using Shenandoah GC, it’s important to handle external memory and native resources properly to ensure efficient garbage collection and avoid potential memory leaks. In this blog post, we’ll explore some best practices for handling external memory and native resources with Shenandoah GC.

1. Native Resources

When dealing with native resources, it’s crucial to release them explicitly when they are no longer needed. Shenandoah GC doesn’t automatically deallocate native resources, so relying on finalizers to release them is not sufficient. Instead, you should use try-finally blocks or the newer try-with-resources construct to ensure proper cleanup.

Here’s an example of how to release a native resource using try-finally:

NativeResource resource = new NativeResource();
try {
    // Use the native resource
    resource.doSomething();
} finally {
    // Release the native resource
    resource.close();
}

Or, you can use try-with-resources to automatically release the native resource:

try (NativeResource resource = new NativeResource()) {
    // Use the native resource
    resource.doSomething();
}

By explicitly releasing native resources, you can prevent memory leaks and improve the efficiency of the Shenandoah GC.

2. External Memory

When working with external memory, Shenandoah GC provides a mechanism known as MemorySegment to handle off-heap memory allocation and deallocation. To allocate external memory with MemorySegment, you can use the allocateNative method:

MemorySegment segment = MemorySegment.allocateNative(size);

After using the external memory, it’s important to explicitly deallocate it to free up the resources. This can be done using the close method:

segment.close();

It’s essential to ensure that all allocated external memory is properly deallocated to prevent memory leaks and maintain optimal performance with Shenandoah GC.

Conclusion

Shenandoah GC offers significant improvements in garbage collection performance, especially for applications with large heaps. However, it’s important to pay attention to handling external memory and native resources properly to avoid potential memory leaks and maintain optimal performance.

By following best practices such as explicitly releasing native resources and deallocating external memory, you can harness the full potential of Shenandoah GC and ensure efficient memory management in your applications.

#garbagecollection #ShenandoahGC