Instead of a String representation of the whole Throwable stack trace incl. cause ThrowableInformation should instead look like this:

public class ThrowableInformation implements Serializable
{
String throwableClassName;
String message;
StackTraceElement[] stackTrace;
ThrowableInformation cause;
}

I omitted get/set and private in this example.

StackTraceElement is perfectly Serializable and did also receive a public c'tor in Java 5 so I guess that the current ThrowableInformation is more or less a relict of log4j which had to stay compatible with older Java versions.

You could obviously keep the getThrowableStrRep() method for compatibility.

This bug is somewhat related to LBCLASSIC-45 because I think that ThrowableInformation should also, as LoggingEvent, be just a dumb data container with no real logic.

The logic to extract the relevant StackTraceElements should IMHO be moved either into Logger or into a static factory method of ThrowableInformation.