JBoss Too Many Files Open Error

Question

Just in the last week I have been having issues with accessing a JBoss (v 4.2.2) web application. When I go to the home page, I get a java.lang.NullPointerException error page. After looking at the JBoss log output, it appears that too many files are open, so how would I go about closing these files? Here is the output from the JBoss log: ``` ERROR [[jsp]] Servlet.service() for servlet jsp threw exception java.io.FileNotFoundException: /usr/local/jboss-4.2.2.GA/server/default/work/jboss.web/localhost/catissuecore/org/apache/jsp/pages/content/home/Error_jsp.java (Too many open files) at java.io.FileOutputStream.open(Native Method) at java.io.FileOutputStream.(FileOutputStream.java:179) at java.io.FileOutputStream.(FileOutputStream.java:70) at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:152) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:306) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:286) at org.apache.jasper.compiler.Compi…

Accepted Answer

First of all you want to determine what file(s) remain open. I'm assuming your server runs linux, so once you know JBoss'es PID

```
ps ax | grep something-that-makes-your-jboss-process-unique
```

you can do

```
ls -l /proc/jbossPID/fd
```

to get a nice list of files that are open at that instant.

Then jbossPID is the number you found with `ps` .

What you're going to do next depends a bit on what you see here:

- you may just need to up the number of files the server can open a bit with ulimit (also look at systemwide limits on your server)

- maybe you spot a number of files your application forgot to close

- ....

But to close these files / get rid of the open files you'll have to restart the JBoss instance.

JBoss Too Many Files Open Error

Solution

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