How to resolve the following error from ejb

Question

Warning: javax.ejb.EJBException
    at com.sun.ejb.containers.BaseContainer.processSystemException(BaseContainer.java:5215)
    at com.sun.ejb.containers.BaseContainer.completeNewTx(BaseContainer.java:5113)
    at com.sun.ejb.containers.BaseContainer.postInvokeTx(BaseContainer.java:4901)
    at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:2045)
    at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:1994)
    at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:222)
    at com.sun.ejb.containers.EJBLocalObjectInvocationHandlerDelegate.invoke(EJBLocalObjectInvocationHandlerDelegate.java:89)
    at com.sun.proxy.$Proxy151.generateExcel(Unknown Source)
    at pageControllers.Backhaul.onClick$exportToExcelBTN(Backhaul.java:176)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.zkoss.zk.ui.event.GenericEventListener.onEvent(GenericEventListener.java:88)
    at org.zkoss.zk.ui.AbstractComponent.onEvent(AbstractComponent.java:2746)
    at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:2717)
    at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:2658)
    at org.zkoss.zk.ui.impl.EventProcessor.process(EventProcessor.java:136)
    at org.zkoss.zk.ui.impl.EventProcessingThreadImpl.process0(EventProcessingThreadImpl.java:536)
    at org.zkoss.zk.ui.impl.EventProcessingThreadImpl.sendEvent(EventProcessingThreadImpl.java:128)
    at org.zkoss.zk.ui.event.Events.sendEvent(Events.java:338)
    at org.zkoss.zk.ui.event.Events.sendEvent(Events.java:348)
    at org.zkoss.zk.ui.AbstractComponent$ForwardListener.onEvent(AbstractComponent.java:3184)
    at org.zkoss.zk.ui.AbstractComponent.onEvent(AbstractComponent.java:2746)
    at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:2717)
    at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:2658)
    at org.zkoss.zk.ui.impl.EventProcessor.process(EventProcessor.java:136)
    at org.zkoss.zk.ui.impl.EventProcessingThreadImpl.process0(EventProcessingThreadImpl.java:536)
    at org.zkoss.zk.ui.impl.EventProcessingThreadImpl.run(EventProcessingThreadImpl.java:463)
Caused by: java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
    at org.jxls.template.SimpleExporter.<clinit>(SimpleExporter.java:25)
    at org.jxls.util.JxlsHelper.<init>(JxlsHelper.java:30)
    at org.jxls.util.JxlsHelper.getInstance(JxlsHelper.java:35)
    at temo.WriteToExcelDocManager.generateExcel(WriteToExcelDocManager.java:56)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1052)
    at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1124)
    at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:5388)
    at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:619)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:800)
    at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:571)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doAround(SystemInterceptorProxy.java:162)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:144)
    at sun.reflect.GeneratedMethodAccessor78.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:861)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:800)
    at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:370)
    at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:5360)
    at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:5348)
    at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:214)
    ... 23 more
Caused by: java.lang.ClassNotFoundException: org.slf4j.LoggerFactory
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    ... 48 more

I have been working on this code for about two weeks now, but nothing is working.

When I use a normal Java code, my code works fine but when I load the code to a zk environment, i get this error.

I have researched and tried all the examples but nothing works.

Answer 1

The error clearly says that "java.lang.ClassNotFoundException: org.slf4j.LoggerFactory". You have to provide one of the various SLF4J implementation .jar files in the classpath, as well as the interface .jar file.