https://bz.apache.org/bugzilla/show_bug.cgi?id=63612
> with a small project reproducing it? Unfortunately not easily extractable/reproducible Maybe : th = new Thread() { @Override public void run() { « do something that requires a connection from the pool » } } ; th.set getContextClassLoader( null ) ; th.run() ; Von: Romain Manni-Bucau <rmannibu...@gmail.com> Gesendet: Donnerstag, 25. Juli 2019 08:06 An: Tomcat Developers List <dev@tomcat.apache.org> Betreff: Re: PooledConnection#connectUsingDriver, Thread.currentThread().getContextClassLoader() is null Le jeu. 25 juil. 2019 à 07:46, Clemens Wyss DEV <clemens...@mysign.ch<mailto:clemens...@mysign.ch>> a écrit : < mais c'était rapide 😉 > >+1 should/can I file a bug? Guess so, with a small project reproducing it? > init at bootstrap the pool (initial size) to ensure it is in one tomcat > classloader how would you achieve this? By setting «initialSize» to «maxSize» in PoolProperties? 1 should be sufficient, however tomcat-jdbc (vs dbcp2 for instance) loads it per connection and not once for all the pool (https://github.com/apache/tomcat/blob/master/modules/jdbc-pool/src/main/java/org/apache/tomcat/jdbc/pool/PooledConnection.java#L196) which is likely 1. Bad for perf but moreover 2. Buggy if the classloader changes between usages of a connection in apps. Loader, driver should be loaded once and potentially the datasource be duplicated per app if needed (driver in the app) IMHO. This would also fix your NPE transitively ;). ---------------------------------------------------------- Von: Romain Manni-Bucau <rmannibu...@gmail.com<mailto:rmannibu...@gmail.com>> Gesendet: Donnerstag, 25. Juli 2019 07:30 An: Tomcat Developers List <dev@tomcat.apache.org<mailto:dev@tomcat.apache.org>> Betreff: Re: PooledConnection#connectUsingDriver, Thread.currentThread().getContextClassLoader() is null +1, there is no real other option AFAIK until you init at bootstrap the pool (initial size) to ensure it is in one tomcat classloader. Le jeu. 25 juil. 2019 à 07:08, Clemens Wyss DEV <mailto:clemens...@mysign.ch<mailto:clemens...@mysign.ch>> a écrit : I tried posting this in the tomcat-users-ml, but I guess it rather fits here: ---------------------------------------------------------- Context: Debian GNU/Linux 9 \n \l java version 1.8.0_162 Tomcat 8.5.35 From time to time we are facing the follwing exception (call stack): ... Caused by: java.sql.SQLException: Unable to load class: org.mariadb.jdbc.Driver from ClassLoader:http://java.net.URLClassLoader@4c873330;ClassLoader:null at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:292) at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:212) at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:736) at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:668) at org.apache.tomcat.jdbc.pool.ConnectionPool.getConnection(ConnectionPool.java:198) at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:132) at org.apache.torque.Torque.getConnection(Torque.java:924) ... 53 common frames omitted Caused by: java.lang.ClassNotFoundException: Unable to load class: org.mariadb.jdbc.Driver from ClassLoader:http://java.net.URLClassLoader@4c873330;ClassLoader:null at org.apache.tomcat.jdbc.pool.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:56) at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:280) ... 59 common frames omitted Caused by: java.lang.ClassNotFoundException: Classloader is null at org.apache.tomcat.jdbc.pool.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:40) ... 60 common frames omitted According to the code (in PooledConnection# connectUsingDriver) Thread.currentThread().getContextClassLoader() returns null Googling for " Thread.currentThread().getContextClassLoader() is null" the common demoniator seems to be `getContextClassLoader can be null`. If this is true there should be a) a null-check in PooledConnection# connectUsingDriver b) if null, then there should be a fallback-Classloader (the system class laoder?) WDYT ? Or any ideas why the given exception pops up from time to time Thx Clemens --------------------------------------------------------------------- To unsubscribe, e-mail: mailto:dev-unsubscr...@tomcat.apache.org<mailto:dev-unsubscr...@tomcat.apache.org> For additional commands, e-mail: mailto:dev-h...@tomcat.apache.org<mailto:dev-h...@tomcat.apache.org>