我是mvel的新手，但我尝试在项目中使用它并面对NoClassDefFoundError：
java.lang.NoClassDefFoundError: Could not initialize class java.net.PlainDatagramSocketImpl
at java.net.DefaultDatagramSocketImplFactory.createDatagramSocketImpl(DefaultDatagramSocketImplFactory.java:70)[:1.7.0_51]
at java.net.DatagramSocket.createImpl(DatagramSocket.java:316)[:1.7.0_51]
at java.net.DatagramSocket.<init>(DatagramSocket.java:229)[:1.7.0_51]
at java.net.DatagramSocket.<init>(DatagramSocket.java:284)[:1.7.0_51]
at java.net.DatagramSocket.<init>(DatagramSocket.java:256)[:1.7.0_51]
at io.fabric8.utils.Ports.isPortFree(Ports.java:180)
at io.fabric8.utils.Ports.findUsedPorts(Ports.java:61)
at io.fabric8.service.PortPlaceholderResolver.resolve(PortPlaceholderResolver.java:77)
at io.fabric8.service.FabricServiceImpl$2.getValue(FabricServiceImpl.java:1047)
at io.fabric8.zookeeper.utils.InterpolationHelper.substVars(InterpolationHelper.java:176)
at io.fabric8.service.FabricServiceImpl.substituteConfigurations(FabricServiceImpl.java:1043)
at io.fabric8.internal.ProfileOverlayImpl.getConfigurations(ProfileOverlayImpl.java:357)
at io.fabric8.configadmin.FabricConfigAdminBridge.updateInternal(FabricConfigAdminBridge.java:117)[71:io.fabric8.fabric-configadmin:1.1.0.SNAPSHOT]
at io.fabric8.configadmin.FabricConfigAdminBridge.access$000(FabricConfigAdminBridge.java:51)[71:io.fabric8.fabric-configadmin:1.1.0.SNAPSHOT]
at io.fabric8.configadmin.FabricConfigAdminBridge$1.run(FabricConfigAdminBridge.java:99)[71:io.fabric8.fabric-configadmin:1.1.0.SNAPSHOT]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)[:1.7.0_51]
at java.util.concurrent.FutureTask.run(FutureTask.java:262)[:1.7.0_51]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)[:1.7.0_51]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)[:1.7.0_51]
at java.lang.Thread.run(Thread.java:744)[:1.7.0_51]
我绝对不知道为什么会这样，有人能告诉我我错过了什么吗？ 有关信息，我在karaf容器中使用mvel 2.1.9。
杰罗姆