in log4j-api-to-jul/src/main/java/org/apache/logging/log4j/tojul/JULLoggerContextFactory.java [37:49]
public JULLoggerContextFactory() {
boolean misconfigured = false;
try {
LoaderUtil.loadClass("org.apache.logging.log4j.jul.LogManager");
misconfigured = true;
} catch (final ClassNotFoundException classNotFoundIsGood) {
LOGGER.debug("org.apache.logging.log4j.jul.LogManager is not on classpath. Good!");
}
if (misconfigured) {
throw new IllegalStateException("log4j-jul JAR is mutually exclusive with the log4j-to-jul JAR"
+ "(the first routes calls from Log4j to JUL, the second from Log4j to JUL)");
}
}