java.lang.NoClassDefFoundError : javafx/collections/MapChangeListener

Question

我尝试在 JavaFX 中实现 MapChangeListener，并在 Intellij Idea (windows) 中运行此示例:

// Use Java Collections to create the List.
Map<String,String> map = new HashMap<String,String>();

// Now add observability by wrapping it with ObservableList.
ObservableMap<String,String> observableMap = FXCollections.observableMap(map);
observableMap.addListener(new MapChangeListener() {
    @Override
    public void onChanged(MapChangeListener.Change change) {
        System.out.println("Detected a change! ");
        logerKuraPI("Detected a change! ");
    }
});

// Changes to the observableMap WILL be reported.
observableMap.put("key 1","value 1");
System.out.println("Size: "+observableMap.size());
logerKuraPI("Size: "+observableMap.size());

// Changes to the underlying map will NOT be reported.
map.put("key 2","value 2");
System.out.println("Size: "+observableMap.size());
logerKuraPI("Size: "+observableMap.size());

它工作得很好，但是当我尝试将代码插入我的 eclipse 项目 (Linux) 时，我收到了这些错误:

java.lang.NoClassDefFoundError: javafx/collections/MapChangeListener
    at java.lang.Class.getDeclaredConstructors0(Native Method)
    at java.lang.Class.privateGetDeclaredConstructors(Class.java:2671)
    at java.lang.Class.getConstructor0(Class.java:3075)
    at java.lang.Class.newInstance(Class.java:412)
    at org.eclipse.equinox.internal.ds.model.ServiceComponent.createInstance(ServiceComponent.java:493)
    at org.eclipse.equinox.internal.ds.model.ServiceComponentProp.createInstance(ServiceComponentProp.java:270)
    at org.eclipse.equinox.internal.ds.model.ServiceComponentProp.build(ServiceComponentProp.java:331)
    at org.eclipse.equinox.internal.ds.InstanceProcess.buildComponent(InstanceProcess.java:620)
    at org.eclipse.equinox.internal.ds.InstanceProcess.buildComponents(InstanceProcess.java:197)
    at org.eclipse.equinox.internal.ds.Resolver.getEligible(Resolver.java:343)
    at org.eclipse.equinox.internal.ds.SCRManager.serviceChanged(SCRManager.java:222)
    at org.eclipse.osgi.internal.serviceregistry.FilteredServiceListener.serviceChanged(FilteredServiceListener.java:109)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.dispatchEvent(BundleContextImpl.java:915)
    at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
    at org.eclipse.osgi.framework.eventmgr.ListenerQueue.dispatchEventSynchronous(ListenerQueue.java:148)
    at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.publishServiceEventPrivileged(ServiceRegistry.java:862)
    at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.publishServiceEvent(ServiceRegistry.java:801)
    at org.eclipse.osgi.internal.serviceregistry.ServiceRegistrationImpl.register(ServiceRegistrationImpl.java:127)
    at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.registerService(ServiceRegistry.java:225)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.registerService(BundleContextImpl.java:464)
    at org.eclipse.equinox.internal.ds.InstanceProcess.registerService(InstanceProcess.java:536)
    at org.eclipse.equinox.internal.ds.InstanceProcess.buildComponents(InstanceProcess.java:213)
    at org.eclipse.equinox.internal.ds.Resolver.buildNewlySatisfied(Resolver.java:473)
    at org.eclipse.equinox.internal.ds.Resolver.enableComponents(Resolver.java:217)
    at org.eclipse.equinox.internal.ds.SCRManager.performWork(SCRManager.java:816)
    at org.eclipse.equinox.internal.ds.SCRManager$QueuedJob.dispatch(SCRManager.java:783)
    at org.eclipse.equinox.internal.ds.WorkThread.run(WorkThread.java:89)
    at org.eclipse.equinox.internal.util.impl.tpt.threadpool.Executor.run(Executor.java:70)
Caused by: java.lang.ClassNotFoundException: javafx.collections.MapChangeListener cannot be found by fileloger_1.0.0.qualifier
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:461)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:372)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:364)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:161)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

谁能帮我找出问题所在吗？即使导入时没有错误:

import javafx.collections.FXCollections;
import javafx.collections.MapChangeListener;
import javafx.collections.ObservableMap;

Answer 1

请阅读此处:https://techblog.bozho.net/runtime-classpath-vs-compile-time-classpath/

我猜测您的编译时依赖项没有问题，但您看到这个问题是因为您没有添加必要的 jar 作为运行时依赖项。

类似问题在这里回答:Why am I getting a NoClassDefFoundError in Java?