title: Log4j2 configuration format with best coverage
body: <p>Log4j2 currently supports 4 configurations formats [1]: XML, JSON, YAML, and properties syntax. I couldn't find in the documentation if all the formats are exactly equivalent in terms of feature coverage.</p>
  <p>Is it possible to use all features of Log4j2 in every format or there are certain formats that lack some expressiveness?</p>
  <p>I vaguely remember in the past that I had some trouble setting up a feature in the property syntax while it was working in the XML syntax; it could be my lack of knowledge at the time instead of a missing feature but if somebody can provide a reference about equivalence or not it would be helpful.</p>
  <p>[1] <a href="https://logging.apache.org/log4j/2.x/manual/configuration.html#" rel="nofollow noreferrer">https://logging.apache.org/log4j/2.x/manual/configuration.html#</a></p>