Synchronizing on ConcurrentModificationException in order to avoid ConcurrentModificationException

exceptions on the list maintained by ConcurrentModificationException, as shown below

java.util.ConcurrentModificationException
        at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:449)
        at java.util.AbstractList$Itr.next(AbstractList.java:420)
        at ch.qos.logback.core.util.StatusPrinter.print(StatusPrinter.java:47)
        at ch.qos.logback.core.util.StatusPrinter.print(StatusPrinter.java:38)
        at ch.qos.logback.audit.server.AuditServerTest.testUnreachable(AuditServerTest.java:137)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:585)
        
This can happen if multiple thread access BasicStatusManager simultaneously.