Hi, Just an FYI. I've been doing early-access testing of JDK9b83 (project Jigsaw modular build from https://jdk9.java.net/jigsaw/) The first call to LoggerFactory.getLogger(Class clazz) fails with the exception: Failed to instantiate [ch.qos.logback.classic.LoggerContext] Reported exception: java.lang.InternalError: unnamed package in named module java.base at jdk.internal.misc.BuiltinClassLoader.definePackage(java.base@9.0/BuiltinClassLoader.java:569) at jdk.internal.misc.BootLoader.definePackage(java.base@9.0/BootLoader.java:123) at java.lang.Class.getPackage(java.base@9.0/Class.java:917) at ch.qos.logback.core.joran.util.StringToObjectConverter.canBeBuiltFromSimpleString(StringToObjectConverter.java:34) at ch.qos.logback.core.joran.util.PropertySetter.computeRawAggregationType(PropertySetter.java:233) at ch.qos.logback.core.joran.util.PropertySetter.computeAggregationType(PropertySetter.java:194) at ch.qos.logback.core.joran.action.NestedComplexPropertyIA.isApplicable(NestedComplexPropertyIA.java:61) at ch.qos.logback.core.joran.spi.Interpreter.lookupImplicitAction(Interpreter.java:237) at ch.qos.logback.core.joran.spi.Interpreter.getApplicableActionList(Interpreter.java:256) at ch.qos.logback.core.joran.spi.Interpreter.startElement(Interpreter.java:144) at ch.qos.logback.core.joran.spi.Interpreter.startElement(Interpreter.java:129) at ch.qos.logback.core.joran.spi.EventPlayer.play(EventPlayer.java:50) at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:149) at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:135) at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:99) at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:49) at ch.qos.logback.classic.util.ContextInitializer.configureByResource(ContextInitializer.java:77) at ch.qos.logback.classic.util.ContextInitializer.autoConfig(ContextInitializer.java:152) at org.slf4j.impl.StaticLoggerBinder.init(StaticLoggerBinder.java:85) at org.slf4j.impl.StaticLoggerBinder.<clinit>(StaticLoggerBinder.java:55) at org.slf4j.LoggerFactory.bind(LoggerFactory.java:141) at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:120) at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:331) at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:283) at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:304) at org.adoptopenjdk.jitwatch.ui.JITWatchUI.<clinit>(JITWatchUI.java:86) at org.adoptopenjdk.jitwatch.launch.LaunchUI.main(LaunchUI.java:18) at sun.reflect.NativeMethodAccessorImpl.invoke0(java.base@9.0/Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(java.base@9.0/NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(java.base@9.0/DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(java.base@9.0/Method.java:530) at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:293) at java.lang.Thread.run(java.base@9.0/Thread.java:746) The program continues but there is no log output. This is with slf4j-api-1.7.7.jar logback-classic-1.1.2.jar logback-core-1.1.2.jar If I remove the logback jars and replace with slf4j-jdk14-1.7.12.jar then it works fine. Cheers, Chris