问题
I was getting this exception but I am not able to understand what is happening there.
Because on compilation time my class able access apache POI classes but on runtime my classes throws exception that he is not able find
org.apache.poi.xssf.usermodel.XSSFWorkbook.
Till now whatever solution is provided on net I have tried everything but not understanding what I am missing.
And weird thing is same code and same Apache POI library working on my friend's eclipse. We both have identical projects. Don't understand what is going on there.
I checked all folder's access where I am referring libraries.
Please share if you have any suggestion.
I am getting the following exception.
!MESSAGE Unhandled event loop exception
!STACK 0
java.lang.NoClassDefFoundError: org/apache/poi/xssf/usermodel/XSSFWorkbook
at com.herzog.pmide.mergedconfigxml.ui.editors.DocumentGenerator.prepareScadaIOListExcel(DocumentGenerator.java:94)
at com.herzog.pmide.mergedconfigxml.ui.editors.DocumentGenerator.scadaIOList(DocumentGenerator.java:77)
at com.herzog.pmide.mergedconfigxml.ui.actions.DocumentGeneratorAction.run(DocumentGeneratorAction.java:47)
at org.eclipse.ui.internal.PluginAction.runWithEvent(PluginAction.java:253)
at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:595)
at org.eclipse.jface.action.ActionContributionItem.access$2(ActionContributionItem.java:511)
at org.eclipse.jface.action.ActionContributionItem$5.handleEvent(ActionContributionItem.java:420)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4353)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1061)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4172)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3761)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1151)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:331)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1032)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:148)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:636)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:331)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:579)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
at com.herzog.pmide.application.Application.start(Application.java:20)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:380)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:235)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:648)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:603)
at org.eclipse.equinox.launcher.Main.run(Main.java:1465)
at org.eclipse.equinox.launcher.Main.main(Main.java:1438)
Caused by: java.lang.ClassNotFoundException: org.apache.poi.xssf.usermodel.XSSFWorkbook cannot be found by com.herzog.pmide.mergedconfigxml.ui_1.0.0.qualifier
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:432)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:345)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:337)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
MANIFEST.MF as follow
Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: Ui
Bundle-SymbolicName: com.herzog.pmide.mergedconfigxml.ui;singleton:=true
Bundle-Version: 1.0.0.qualifier
Bundle-Activator: com.herzog.pmide.mergedconfigxml.ui.Activator
Bundle-Vendor: Example
Require-Bundle: org.eclipse.ui,
org.eclipse.core.runtime,
org.eclipse.core.resources,
org.eclipse.emf.ecore.xmi,
org.eclipse.emf.edit.ui,
com.herzog.pmide.machinelib.model.edit,
org.eclipse.ui.forms,
org.eclipse.ui.workbench,
org.eclipse.ui.ide,
com.herzog.pmide.mergedconfigxml.model.edit,
org.eclipse.gef,
com.herzog.pmide.tools.importutility,
com.herzog.pmide.machinelib.model,
org.eclipse.swt,
org.eclipse.emf.query,
com.herzog.pmide.mergedconfigxml.model,
org.eclipse.ui.editors,
org.eclipse.emf.validation,
org.eclipse.emf.validation.ui,
org.slf4j.api,
org.junit,
org.eclipse.emf.compare,
org.eclipse.emf.compare.edit,
org.eclipse.emf.compare.ide.ui,
org.eclipse.compare,
org.apache.commons.io,
org.eclipse.core.filesystem,
de.vonloesch.pdf4Eclipse,
de.vonloesch.pdf4eclipse.help,
com.herzog.pmide.routingline.model
Bundle-ActivationPolicy: lazy
Bundle-ClassPath: .
Export-Package: com.herzog.pmide.mergedconfigxml.ui,
com.herzog.pmide.mergedconfigxml.ui.editors.unitconfig,
com.herzog.pmide.mergedconfigxml.ui.views
Bundle-Localization: OSGI-INF/l10n/message
build.properties as follow
source.. = src/
output.. = bin/
bin.includes = META-INF/,\
.,\
plugin.xml,\
icons/,\
OSGI-INF/l10n/message.properties
回答1:
A plugin can only access classes in other plugins or in jars included in the plugin which are included in the bundle class path. Setting the Java Build Path properties does not configure the plugin correctly.
Add all the jars you need to the plugin, usually these are put in a 'lib' directory.
Update the build.properties to include these jars in the 'bin.includes' section. For example:
source.. = src/
output.. = bin/
bin.includes = META-INF/,\
.,\
plugin.properties,\
plugin.xml,\
lib/,\
lib/jogg-0.0.7.jar,\
lib/jorbis-0.0.15.jar,\
lib/vorbisspi1.0.2.jar
Here I have 3 jars in a lib directory (these are not the POI jars, this is just an example from one of my projects).
Update the MANIFEST.MF and set the Bundle-Classpath to include the jars. You can do this in the MANIFEST.MF editor in the 'Runtime' tab in the 'Classpath' section (use the Add... button to the right of the list and choose the libraries in the plugin). Be sure to leave the entry for '.'. Your MANIFEST.MF should end up containing a `Bundle-Classpath' entry like this:
Bundle-ClassPath: .,
lib/jogg-0.0.7.jar,
lib/jorbis-0.0.15.jar,
lib/vorbisspi1.0.2.jar
来源：https://stackoverflow.com/questions/44193879/java-lang-noclassdeffounderror-org-apache-poi-xssf-usermodel-xssfworkbook