On Dec 27, 2007 the vulture thread in the ObjectProxyCache was commented out with "vulture daemon thread prevents finalization, find alternative approach":

97a9e71#diff-ab6ac0f472eb3dc6d6d659b83ff81872L87

The issue is, on JRuby v1.7.16.1 we are seeing what might be a thread leak with the format of:

"ObjectProxyCache 75 vulture"
"ObjectProxyCache 16 vulture"
"ObjectProxyCache 60 vulture"

What is strange, is that the checkin changes the thread name as follows:

-        vulture = new Thread("ObjectProxyCache vulture") {
+        this.vulture = new Thread("ObjectProxyCache "+id+" vulture") {

And then commented out calling it. Two things. First, why would the developer change the name and then comment it out? Second, we are actually seeing the new format in our thread list, not the old one before it was commented out. I have searched the JRuby 1.7.16.1 codebase, and see the only place that vultures is referenced is here:

https://github.com/jruby/jruby/blob/1.7.16.1/core/src/main/java/org/jruby/javasupport/util/ObjectProxyCache.java

This is private, although with reflection you might be able to get at it. But we are not calling it anywhere in our Java code or Ruby scripts. And yet it is appearing in our thread list.

Any ideas on how this might be getting spawned regardless?