Log4j comes with several appenders that do things like console and file output and send logging messages using email or JMS (Java Message Service). Log4j also includes a socket-based appender ...

Log4j, an open source project, allows developers to control which log statements are output with arbitrary granularity. It's fully configurable at runtime by using external configuration files.

If you're not certain whether your Java project is free from Log4j vulnerabilities, you should try this easy-to-use scanning tool immediately.

"With Log4j, preventing the entire class of bugs that cause it is going to be hard with today's technology, but stuff like fuzzing and safe-by-default language/library design can help a lot.