[LOG4J2-3420] getlogger() UnsupportedOperationException when loaded by Class.forName()

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Bug
• Affects Version/s: 2.17.2
• Component/s: API

Environment

Several versions of log4j 2.

Tried with several versions of jdk (the exception shown is jdk-17).

 

• Assignee: Ralph Goers
• Reporter: Ernie Rael
• Created: 01/Mar/22 07:54
• Updated: 11/Mar/22 16:21
• Resolved: 03/Mar/22 04:07

Description

Exception arises when this class is used in the NetBeans guiBuilder.

public class MyTextField extends JTextField {
final private static Logger logger = LogManager.getLogger();
public MyTextField(){}
}

Get the following exception when the bean is selected to drop on the gui.

INFO [org.netbeans.modules.form.MetaComponentCreator]: Cannot load component class play.MyTextField from unknown source.
The class itself was found, but there was a problem initializing it, e.g. due to an exception in static initializer, or failure in loading an additional class needed by the component class. Check the attached exception.
java.lang.UnsupportedOperationException: No class provided, and an appropriate one cannot be found.
at org.apache.logging.log4j.LogManager.callerClass(LogManager.java:573)
at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:598)
at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:585)
at play.MyTextField.<clinit>(MyTextField.java:35)
Caused: java.lang.ExceptionInInitializerError
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:467)
at org.netbeans.modules.form.project.ClassPathUtils.loadClass(ClassPathUtils.java:89)

This exception similarly occurs with clazz.newInstance(), which is sometimes used by the guiBuilder. It also occurs if the getLogger is in the constructor rather than a static.

As a workaround, since I can compile the gui component, I'm invoking Stuff.getLogger()

public class Stuff {
static Logger getLogger() {
    try {
        return LogManager.getLogger(StackLocatorUtil.getCallerClass(2));
    } catch(UnsupportedOperationException ex) {}
    return LogManager.getRootLogger();
}
}