Andreas Bergander created SLF4J-438: --------------------------------------- Summary: IllegalAccessError in MDC when using Java 10 Key: SLF4J-438 URL: https://jira.qos.ch/browse/SLF4J-438 Project: SLF4J Issue Type: Bug Affects Versions: 1.7.25 Environment: Java 10 slf4j-api-1.7.25 slf4j-log4j12-1.7.25 Reporter: Andreas Bergander Assignee: SLF4J developers list When using MDC and log4j I get an IllegalAccessError during initialization. {noformat} java.lang.IllegalAccessError: tried to access field org.apache.log4j.MDC.mdc from class org.apache.log4j.MDCFriend         at org.apache.log4j.MDCFriend.fixForJava9(MDCFriend.java:11)         at org.slf4j.impl.Log4jMDCAdapter.<clinit>(Log4jMDCAdapter.java:38)         at org.slf4j.impl.StaticMDCBinder.getMDCA(StaticMDCBinder.java:59)         at org.slf4j.MDC.bwCompatibleGetMDCAdapterFromBinder(MDC.java:99)         at org.slf4j.MDC.<clinit>(MDC.java:108) {noformat}  I guess package private fields are not accessible between different jar-files anymore in Java 10. Or am I doing something wrong?   -- This message was sent by Atlassian JIRA (v7.3.1#73012)