Exception in thread "main" java.lang.reflect.InvocationTargetException
	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:497)
	at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:58)
Caused by: java.lang.NoClassDefFoundError: org/eclipse/californium/elements/util/NamedThreadFactory
	at org.eclipse.californium.core.CoapServer.<init>(CoapServer.java:163)
	at org.eclipse.californium.core.CoapServer.<init>(CoapServer.java:120)
	at iot.main.device.DeviceClient.main(DeviceClient.java:34)
	... 5 more
Caused by: java.lang.ClassNotFoundException: org.eclipse.californium.elements.util.NamedThreadFactory
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 8 more