Why does tomcat logging stop after redeploy?

Question

I can't seem to get java.util.logging to work with tomcat after I redeploy a webapp. Here is a very simple Servlet as a test case;

package test;

import java.util.logging.Logger;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;

@WebServlet(name = "TestLogServlet", urlPatterns = {"/TestLogServlet"}, loadOnStartup=1)
public class TestLogServlet extends HttpServlet {

    private Logger logger = Logger.getLogger(TestLogServlet.class.getName());

    @Override
    public void init(ServletConfig config) throws ServletException {
        super.init(config); 
        System.out.println("my log message to system.out");
        logger.info("my log message to logger");
    }
       
}

If I have the webapp installed, then start tomcat, I will see in the logs (catalina.out) the following, as expected;

my log message to system.out
20-Mar-2023 10:56:37.035 INFO [main] test.TestLogServlet.init my log message to logger

Both the system.out and the logger message.

If I then undeploy the webapps, then redeploy it in the running tomcat, all I will see in the logs are;

my log message to system.out

Nothing else will appear comming from java.util.logger.

What am I missing, or doing wrong? It's driving me mad!

A bit of an update... This is why ...

==> catalina.out <==
my log message to system.out

==> catalina.2023-03-20.log <==
20-Mar-2023 11:42:04.041 INFO [http-nio-8080-exec-16] test.TestLogServlet.init my log message to logger

After a redeploy, it goes to catalina.2023-03-20.log, not catalina.out. When you restart tomcat it goes to catalina.2023-03-20.log and catalina.out!!

So, how does I get the logger messages to ALWAYS go to catalina.out?

I tired this on a tomcat8, and it does seem to always go to catalina.out there.

Answer 1

You could custom the log format through the configure file there should be a default file log4j.properties in path $CATALINA_BASE/lib

Create one, if there isn't.

and add the following to logging.properties file

catalina.org.apache.juli.FileHandler.rotatable = false
localhost.org.apache.juli.FileHandler.rotatable = false
manager.org.apache.juli.FileHandler.rotatable = false
host-manager.org.apache.juli.FileHandler.rotatable = false

You could also read the Tomcat logging documentation.