While working on a new JUnit test I ran into this issue where no logging
was happening and I saw this printed to system.err:
ERROR StatusLogger Unable to invoke factory method in class class
org.apache.logging.log4j.core.appender.RollingRandomAccessFileAppender for
element RollingRandomAccessFile.
ERROR StatusLogger Null object returned for RollingRandomAccessFile in
Appenders.
ERROR StatusLogger Unable to locate appender RollingRandomAccessFile for
logger
The problem is that this message does not explain the cause of the problem.
To many users this message will just say "log4j is broken".
It turned out that I had misconfigured the test (used
a TimeBasedTriggeringPolicy while filePattern didn't have a date).
That is key information that should be reported by the error handling.
So...
PluginBuilder.build() now has two try/catch blocks where the catch looks
like this:
} catch (final Exception e) {
LOGGER.catching(Level.DEBUG, e);
LOGGER.error("Unable to invoke factory method in class {} for element
{}.", this.clazz, this.node.getName());
return null;
}
I am going to change change the DEBUG to ERROR, so we get this:
LOGGER.catching(Level.ERROR, e);
That will print a long-ish stack trace, which may not be the most
user-friendly, but at least it will give the user the information they need
to solve the problem.
I don't know how error reporting worked before PluginBuilder, there may be
a better format... Please feel free to improve on this.
