# How to use "ECS logging Java"? **URL:** \ **Category:** APM\ **Created:** [November 4, 2019, 7:55am UTC](https://discuss.elastic.co/t/how-to-use-ecs-logging-java/206348 "2019-11-04T07:55:37Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![wajika](https://avatars.discourse-cdn.com/v4/letter/w/977dab/32.png) [@wajika](https://discuss.elastic.co/u/wajika)\ **Post date:** [November 4, 2019, 7:55am UTC](https://discuss.elastic.co/t/how-to-use-ecs-logging-java/206348/1 "2019-11-04T07:55:37Z")
I add log4j2-ecs-layout dependency to the application ![apm](https://us1.discourse-cdn.com/elastic/original/3X/a/1/a1fc11291c82afb1bb24a51b308badec66143079.png) log4j2.xml ![logapm](https://us1.discourse-cdn.com/elastic/original/3X/7/f/7f712edd4aa5fcdc807acf6137abee6690c505eb.png) COMMAND: ————————————————————— java -javaagent:/root/elastic-apm-agent-1.11.0.jar -Delastic.apm.service\_name=my-cool-service -Delastic.apm.enable\_log\_correlation=true -Delastic.apm.application\_packages=org.example,org.another.example -Delastic.apm.server\_urls=http://localhost:8200 -jar target/dj-development-system-0.0.3-RELEASE.jar I don't know how to reference "ecsjsonserializer" How can I solve this error? LOG： ————————————————————— 2019-11-04 02:24:03.536 [apm-server-healthcheck] INFO co.elastic.apm.agent.report.ApmServerHealthChecker - Elastic APM server is available: { "build\_date": "2019-09-27T06:58:27Z", "build\_sha": "971d864356e4438bf4a799a1fa052cfd0ce680b4", "version": "7.4.0"} 2019-11-04 02:24:03.635 [main] INFO co.elastic.apm.agent.configuration.StartupInfo - Starting Elastic APM 1.11.0 as my-cool-service on Java 11.0.5 (Oracle Corporation) Linux 3.10.0-862.el7.x86\_64 2019-11-04 02:24:03.649 [apm-remote-config-poller] INFO co.elastic.apm.agent.configuration.ApmServerConfigurationSource - Received new configuration from APM Server: {transaction\_sample\_rate=1} Exception in thread "main" java.lang.reflect.InvocationTargetException at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:566) at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48) at org.springframework.boot.loader.Launcher.launch(Launcher.java:87) at org.springframework.boot.loader.Launcher.launch(Launcher.java:50) at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51) Caused by: java.lang.NoClassDefFoundError: co/elastic/logging/EcsJsonSerializer at co.elastic.logging.log4j2.EcsLayout.(EcsLayout.java:97) at co.elastic.logging.log4j2.EcsLayout.(EcsLayout.java:63) at co.elastic.logging.log4j2.EcsLayout$Builder.build(EcsLayout.java:408) at co.elastic.logging.log4j2.EcsLayout$Builder.build(EcsLayout.java:324) at org.apache.logging.log4j.core.config.plugins.util.PluginBuilder.build(PluginBuilder.java:122) at org.apache.logging.log4j.core.config.AbstractConfiguration.createPluginObject(AbstractConfiguration.java:958) at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:898) at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:890) at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:890) at org.apache.logging.log4j.core.config.AbstractConfiguration.doConfigure(AbstractConfiguration.java:513) at org.apache.logging.log4j.core.config.AbstractConfiguration.initialize(AbstractConfiguration.java:237) at org.apache.logging.log4j.core.config.AbstractConfiguration.start(AbstractConfiguration.java:249) at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:545) at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:617) at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:634) at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:229) at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:153) at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45) at org.apache.logging.log4j.LogManager.getContext(LogManager.java:194) at org.apache.commons.logging.LogFactory$Log4jLog.(LogFactory.java:199) at org.apache.commons.logging.LogFactory$Log4jDelegate.createLog(LogFactory.java:166) at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:109) at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:99) at org.springframework.boot.SpringApplication.(SpringApplication.java:189) at com.djcps.djfileserver.DjdevelopmentsysApplication.main(DjdevelopmentsysApplication.java:34) ... 8 more Caused by: java.lang.ClassNotFoundException: co.elastic.logging.EcsJsonSerializer at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:471) at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588) at org.springframework.boot.loader.LaunchedURLClassLoader.loadClass(LaunchedURLClassLoader.java:93) at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) ... 33 more ---
**Author:** ![felixbarny](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/felixbarny/32/27341_2.png) [@felixbarny](https://discuss.elastic.co/u/felixbarny)\ **Post date:** [November 4, 2019, 8:06am UTC](https://discuss.elastic.co/t/how-to-use-ecs-logging-java/206348/2 "2019-11-04T08:06:38Z")
Make sure to include the transitive dependency ecs-logging-core when using manual dependency management. ---
**Author:** ![wajika](https://avatars.discourse-cdn.com/v4/letter/w/977dab/32.png) [@wajika](https://discuss.elastic.co/u/wajika)\ **Post date:** [November 4, 2019, 8:30am UTC](https://discuss.elastic.co/t/how-to-use-ecs-logging-java/206348/3 "2019-11-04T08:30:24Z")
I compiled ecs-logging-java-0.1.2.tar.gz and generated three files. log4j-ecs-layout-0.1.2.jar log4j-ecs-layout-0.1.2-javadoc.jar log4j-ecs-layout-0.1.2-sources.jar I've already referenced ‘log4j-ecs-layout-0.1.2.jar’ in the pom.xml file ---
**Author:** ![wajika](https://avatars.discourse-cdn.com/v4/letter/w/977dab/32.png) [@wajika](https://discuss.elastic.co/u/wajika)\ **Post date:** [November 4, 2019, 8:31am UTC](https://discuss.elastic.co/t/how-to-use-ecs-logging-java/206348/4 "2019-11-04T08:31:47Z")
I've already referenced ‘log4j-ecs-layout-0.1.2.jar’ in the pom.xml file. But it doesn't work ---
**Author:** ![wajika](https://avatars.discourse-cdn.com/v4/letter/w/977dab/32.png) [@wajika](https://discuss.elastic.co/u/wajika)\ **Post date:** [November 4, 2019, 9:08am UTC](https://discuss.elastic.co/t/how-to-use-ecs-logging-java/206348/5 "2019-11-04T09:08:40Z")
Sorry, I found out I made a mistake. I forgot to use the 'ECS logging core' package ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [November 25, 2019, 5:08am UTC](https://discuss.elastic.co/t/how-to-use-ecs-logging-java/206348/6 "2019-11-25T05:08:41Z")
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