I'm trying to use one of the Apache Commons libraries (Math 3.3) in Java with Eclipse. (JDK 1.7 and Eclipse 3/JDT 3.7) And I can't get away from NoClassDefFoundError ...

Proof-of-concept exploits for a critical zero-day vulnerability in the ubiquitous Apache Log4j Java-based logging library are currently being shared online, exposing home users and enterprises alike ...