我试图让代码超过这一行：
JAXBContext jaxbContext = JAXBContext.newInstance("foo.bar.package");
它抛出了一个异常——这是堆栈跟踪——有什么想法吗？
SEVERE: Unhandled exception or error intercepted
java.lang.NoClassDefFoundError: javax/activation/DataSource
at com.sun.xml.bind.v2.model.impl.RuntimeBuiltinLeafInfoImpl.<clinit>(RuntimeBuiltinLeafInfoImpl.java:172)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeInfoSetImpl.<init>(RuntimeTypeInfoSetImpl.java:25)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.createTypeInfoSet(RuntimeModelBuilder.java:78)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.createTypeInfoSet(RuntimeModelBuilder.java:41)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.<init>(ModelBuilder.java:97)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.<init>(RuntimeModelBuilder.java:44)
at com.sun.xml.bind.v2.runtime.JAXBContextImpl.getTypeInfoSet(JAXBContextImpl.java:320)
at com.sun.xml.bind.v2.runtime.JAXBContextImpl.<init>(JAXBContextImpl.java:198)
at com.sun.xml.bind.v2.ContextFactory.createContext(ContextFactory.java:76)
at com.sun.xml.bind.v2.ContextFactory.createContext(ContextFactory.java:55)
at com.sun.xml.bind.v2.ContextFactory.createContext(ContextFactory.java:124)
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(ContextFinder.java:132)
at javax.xml.bind.ContextFinder.find(ContextFinder.java:286)
at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:358)
at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:323)
at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:244)