Hi All, We started testing SLF4J and logback projects using Java 9, more specifically build 154. As such, I would appreciate if you could add the following details onto the Quality Outreach wiki page. Contact: Ceki Gülcü SLF4J mailing list slf4j-dev AT qos DOT ch Logback mailing list logback-dev AT qos DOT ch Initial testing results ======================= Initial testing indicates that log4j version 1.2.x is unable to parse the result of the call System.getProperties("java.version"). The returned string is "9-ea". However, log4j 1.2.x expects a string in the form "1\.*", for example "1.6", "1.7" etc. If the string is not in the correct form, log4j 1.2.x conservatively assumes that it is running under Java 1.1 and disables certain important functions, such as MDC support. The code in question is the static initializer of the org.apache.log4j.helpers.Loader class. Log4j 1.2.x is no longer maintained. However, there are innumerably many projects which still use log4j 1.2.x. I would suggest that the string returned be in the form "1\.9*" such as "1.9EA" so as not to break log4j 1.2.x under Java 9. Many thanks in advance for taking the above into consideration. Best regards, -- Ceki Gülcü