Detecting out of memory errors

Question

I would like to provide my system with a way of detecting whether out of memory exception has occurred or not. The aim for this exercise is to expose this flag through JMX a

Answer 1

There is an article based on the post that Scorpion has already given a link to.

The technique is again based on using MemoryPoolMXBean and subscribing to the "memory threshold exceeded" event, but it's slightly different from what was described in original post.

Author states that when you subscribe for the plain "memory threshold exceeded" event, there is a possibility of "false alarm". Imagine a situation when the memory consumption is above the threshold, but there will be a garbage collection performed soon and a lot of the memory is freed after that. In fact that situation is quite common in real world applications.

Fortunately, there is another threshold, "collection usage threshold", and a corresponding event, which is fired based on memory consumption right after garbage collection. When you receive that event, you can be much more confident you're running out of memory.