On 18/04/2016 10:18, Mark Thomas wrote:
Hi,
The Apache Tomcat community was asked by Rory O'Donnell for feedback on
JDK 9 + Project Jigsaw. Having provided that feedback we were directed
here so I have reproduced that feedback below.
I've started testing Tomcat trunk with JDK 9 + Project Jigsaw and it
looks like we are going to hit a bunch of problems related to Tomcat's
memory leak protection.
The short version is there are lots of JDK calls that can result in a
reference being retained to the current class loader. If that class
loader is the web application class loader it often ends up being pinned
in memory. This triggers a memory leak when the web application is
reloaded since the web application class loader is not eligible for GC.
Tomcat generally uses reflection to find these problems. It then does
one of two things:
- If the JRE provides an API the application developer should have used
to clean up the reference, Tomcat does this for them and then logs a
very loud error message telling the developer they need to fix their app.
- If there is nothing the developer could have done to avoid the
problem, Tomcat cleans it up. Usually this is via reflection again.
Reporting this second class of issues as JRE bugs has been on my TODO
list for a long time. It looks like Java 9 is going to bump this to the
top of the list.
I remember you brought this up on core-libs-dev [1] and the suggestion
at the time was to create bugs for any of the issues that are still
relevant. So yes, bumping the priority on that would be good.
On the RMI issue then it would be good to start a thread specifically on
this topic on core-libs-dev.
-Alan
[1]
http://mail.openjdk.java.net/pipermail/core-libs-dev/2014-September/028823.html
