How do you detect low memory situations within the java virtual machine?

Question

I've been getting some OutOfMemory errors lately in my application. Is it possible to detect ahead of time when the virtual machine is running low on memory? In other words to preemptively deal with OutOfMemory errors before they actually occur?

Answer 1

Java (as of Java 5) now has a standard JMX bean that can be used to receive low memory notification. See java.lang.management.MemoryMXBean.