Java AppDomain like abstraction?

Question

I'm curious if there are any Java abstractions that are similar to .Net's AppDomain.

In particular, I'm curious because I've found that with our Coldfusion/J2EE server we need to restart it every few days due to a slow memory leak that we haven't been able to easily track down yet. This can wreck our long-running processes and we'd really like a way to slowly just push people to new JVMs as they age past a certain time period/memory threshold.

From my limited .Net experience I'm pretty sure that this is one situation that IIS and AppDomains are able to manage fairly seamlessly by recycling AppDomains that come under memory pressure. Please let me know if I'm way off on AppDomains helping in this scenario.

Any suggestions?

Answer 1

I think Yiannis's answer here is a little misleading. Simply saying "no, you can't" is not the whole story. The question is focused on unloading Java classes in a server process to remove leaky code from the JVM process without a process restart. The OP is not asking for the process-like memory isolation feature that an AppDomain gives, but the ability to unload classes in a running JVM. I say process-like, since under the hood an AppDomain is not a process, but enjoys some of the isolation aspects that a first-class process is afforded by the operating system. The isolate JSR mentioned is referring to this 'process-like' isolation. Unloading java ClassLoaders and thus classes, without cycling the OS process hosting the JVM is possible. A couple of methods are mentioned here: SO 148681. It is not trivial, or elegant to do this in Java, but it is possible.