The issue is with your log4j jars. They are not matching up with each other.POI 5.2.3 defaults to log4j-api 2.18.0. There are a lot of things that go wrong with deploying logging jars and I think you would be better off reading the log4j docs and checking stackoverflow.com for details about how to set up log4j logging in Tomcat. Tomcat might have a different version of log4j and you might need to do some configuration of your web.xml deployment descriptor - again best to ask a Tomcat expert about that.
On Monday 31 October 2022 at 16:49:48 GMT, Campbell, Lance <la...@illinois.edu> wrote: I just started working with POI. . I am just writing out an Excel document. I pulled down the project using Maven for 5.2.3 . In eclipse everything compiled fine. When I deployed the software to Tomcat I got this error message: Exception in thread "Thread-6" java.lang.NoSuchMethodError: org.apache.logging.log4j.util.LoaderUtil.getClassLoaders()[Ljava/lang/ClassLoader; The line it was failing on is the last line listed below "new XSSFWorkbook()": XSSFWorkbook workbook = null; // ClassLoader classloader = org.apache.poi.poifs.filesystem.POIFSFileSystem.class.getClassLoader(); URL res = classloader.getResource("org/apache/poi/xssf/usermodel/XSSFWorkbook.class"); String path = res.getPath(); System.out.println("POI Core came from " + path); // // line with error is below workbook = new XSSFWorkbook(); After reading some documentation I put in the code directly above the line that was failing. The display showed that the code was found. POI Core came from file:/folder1/folder2/folder3/application/webapps/ROOT/WEB-INF/lib/poi-ooxml-5.2.2.jar!/org/apache/poi/xssf/usermodel/XSSFWorkbook.class I tried rebuilding the project in Eclipse and also updating Maven. After redeploying I kept getting the same error message. I then changed the version to 5.2.2 and everything worked fine. I am wondering if there might be an issue with 5.2.3 . MAVEN that did NOT work: <dependencies> <dependency> <groupId>webserviceslib</groupId> <artifactId>webserviceslib</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi</artifactId> <version>5.2.3</version> </dependency> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi-ooxml</artifactId> <version>5.2.3</version> </dependency> </dependencies> MAVEN that does work: <dependencies> <dependency> <groupId>webserviceslib</groupId> <artifactId>webserviceslib</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi</artifactId> <version>5.2.2</version> </dependency> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi-ooxml</artifactId> <version>5.2.2</version> </dependency> </dependencies> Thanks, Lance Campbell Web Services @ Public Affairs @ University of Illinois