Error in confluence ) crash and problem to start
Asked by Julian Castello:

Hello,

for any reason this morning, confluence was crashed. I restarted the service and all work again. I wanted create a log in log analyzer but after few minutes, it's crashed again.

I uploaded log on my cloud : [https://nastrolom.synology.me/index.php/s/ZmNwkZEFukQzJEg](https://nastrolom.synology.me/index.php/s/ZmNwkZEFukQzJEg?) (pwd : confluence2019!)

Another problem: Every time i restart the server, normally confluence will start automatically but every time i have a status running (exited). I found the following line in catalina.out (shared too in the cloud):

01-Sep-2019 13:36:58.801 WARNING \[localhost-startStop-3\] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesJdbc The web application \[ROOT\] registered the JDBC driver \[org.hsqldb.jdbc.JDBCDriver\] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.  
01-Sep-2019 13:36:58.801 WARNING \[localhost-startStop-3\] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesJdbc The web application \[ROOT\] registered the JDBC driver \[com.github.gquintana.metrics.sql.Driver\] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.  
01-Sep-2019 13:36:58.801 WARNING \[localhost-startStop-3\] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesJdbc The web application \[ROOT\] registered the JDBC driver \[org.h2.Driver\] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.  
01-Sep-2019 13:36:58.801 WARNING \[localhost-startStop-3\] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesJdbc The web application \[ROOT\] registered the JDBC driver \[org.postgresql.Driver\] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.  
01-Sep-2019 13:36:58.802 WARNING \[localhost-startStop-3\] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesJdbc The web application \[ROOT\] registered the JDBC driver \[net.sourceforge.jtds.jdbc.Driver\] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.  
01-Sep-2019 13:36:58.802 WARNING \[localhost-startStop-3\] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesJdbc The web application \[ROOT\] registered the JDBC driver \[com.mysql.fabric.jdbc.FabricMySQLDriver\] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.  
01-Sep-2019 13:36:58.802 WARNING \[localhost-startStop-3\] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesJdbc The web application \[ROOT\] registered the JDBC driver \[com.microsoft.sqlserver.jdbc.SQLServerDriver\] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.  
01-Sep-2019 13:36:58.802 WARNING \[localhost-startStop-3\] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesJdbc The web application \[ROOT\] registered the JDBC driver \[com.mysql.jdbc.Driver\] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.  
01-Sep-2019 13:36:58.802 WARNING \[localhost-startStop-3\] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application \[ROOT\] appears to have started a thread named \[Abandoned connection cleanup thread\] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:

To solve the starting i do that :

i kill the process confluence

ps -ef \| grep confluence

kill PID

Could be that?

Thanks!


Answers:
author: Stan Ry
body: Hi, I believe it's not actually a memory leak caused by JDBC connectivity driver, but rather some preventive actions taken by Apache's Catalina. It looks like the driver was unable to connect to the DB source. Since the driver did not unregister itself automatically, Catalina attempted to do so forcibly.

I would look into DB connection issues, [check this article for more details](https://confluence.atlassian.com/confkb/connections-could-not-be-acquired-from-the-underlying-database-104825087.html).

comments: author: Julian Castello
body: I will check that thank you