好的，我不知所措。我在这一行上有一个Null指针：
JAXBContext context = JAXBContext.newInstance( X3D.class );
这是输出错误的事情：
Exception in thread "main" java.lang.NullPointerException
at com.sun.xml.internal.bind.v2.runtime.ClassBeanInfoImpl.checkOverrideProperties(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.ClassBeanInfoImpl.<init>(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.getOrCreate(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.getOrCreate(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.property.SingleElementNodeProperty.<init>(Unknown Source)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.property.PropertyFactory.create(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.ClassBeanInfoImpl.<init>(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.getOrCreate(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.ClassBeanInfoImpl.<init>(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.getOrCreate(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.ClassBeanInfoImpl.<init>(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.getOrCreate(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.getOrCreate(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.property.ArrayElementProperty.<init>(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.property.ArrayElementNodeProperty.<init>(Unknown Source)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.property.PropertyFactory.create(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.ClassBeanInfoImpl.<init>(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.getOrCreate(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.getOrCreate(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.property.SingleElementNodeProperty.<init>(Unknown Source)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.property.PropertyFactory.create(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.ClassBeanInfoImpl.<init>(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.getOrCreate(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.<init>(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.<init>(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl$JAXBContextBuilder.build(Unknown Source)
at com.sun.xml.internal.bind.v2.ContextFactory.createContext(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at javax.xml.bind.ContextFinder.newInstance(Unknown Source)
at javax.xml.bind.ContextFinder.newInstance(Unknown Source)
at javax.xml.bind.ContextFinder.find(Unknown Source)
at javax.xml.bind.JAXBContext.newInstance(Unknown Source)
at javax.xml.bind.JAXBContext.newInstance(Unknown Source)
at com.prim.esaa.gui.x3d.MyXmlWriter.myWriteFile(MyXmlWriter.java:159)
at com.prim.esaa.gui.x3d.MyXmlWriter.myWrite(MyXmlWriter.java:199)
at com.prim.esaa.gui.x3d.Sim3DAnimator.writeXMLoutput(Sim3DAnimator.java:266)
at com.prim.esaa.gui.x3d.Sim3DAnimator.initModels(Sim3DAnimator.java:212)
at com.prim.esaa.gui.x3d.Sim3DAnimator.main(Sim3DAnimator.java:141)
我意识到并非所有的代码都在那里，我可以添加更多但是如果我理解正确，这个命令设置的东西，并不完全依赖于我的任何其他变量。它正在工作，然后就停止了。我不知道为什么。
它一遍又一遍地说“未知来源”，但我包含路径和类X3D以便它应该没问题。
感谢。