hi, I don't quite well understand what do I do wrong.\ can you help me please?
ERROR [2017-06-29 08:21:53,695] ({qtp1521110008-116} InterpreterFactory.java[createRepl]:246) - exception checking server classloader driver java.lang.ClassNotFoundException: org.apache.zeppelin.spark.SparkInterpreter at java.net.URLClassLoader$1.run(URLClassLoader.java:366) at java.net.URLClassLoader$1.run(URLClassLoader.java:355) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:354) at java.lang.ClassLoader.loadClass(ClassLoader.java:425) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308) at java.lang.ClassLoader.loadClass(ClassLoader.java:358) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:191) at org.apache.zeppelin.interpreter.InterpreterFactory.createRepl(InterpreterFactory.java:241) at org.apache.zeppelin.interpreter.InterpreterFactory.createInterpretersForNote(InterpreterFactory.java:206) at org.apache.zeppelin.interpreter.InterpreterFactory.createOrGetInterpreterList(InterpreterFactory.java:332) at org.apache.zeppelin.interpreter.InterpreterFactory.getInterpreter(InterpreterFactory.java:395) at org.apache.zeppelin.notebook.Note.run(Note.java:600) at org.apache.zeppelin.socket.NotebookServer.persistAndExecuteSingleParagraph(NotebookServer.java:1641) at org.apache.zeppelin.socket.NotebookServer.runAllParagraphs(NotebookServer.java:1588) at org.apache.zeppelin.socket.NotebookServer.onMessage(NotebookServer.java:268) at org.apache.zeppelin.socket.NotebookSocket.onWebSocketText(NotebookSocket.java:59) at org.eclipse.jetty.websocket.common.events.JettyListenerEventDriver.onTextMessage(JettyListenerEventDriver.java:128) at org.eclipse.jetty.websocket.common.message.SimpleTextMessage.messageComplete(SimpleTextMessage.java:69) at org.eclipse.jetty.websocket.common.events.AbstractEventDriver.appendMessage(AbstractEventDriver.java:65) at org.eclipse.jetty.websocket.common.events.JettyListenerEventDriver.onTextFrame(JettyListenerEventDriver.java:122) at org.eclipse.jetty.websocket.common.events.AbstractEventDriver.incomingFrame(AbstractEventDriver.java:161) at org.eclipse.jetty.websocket.common.WebSocketSession.incomingFrame(WebSocketSession.java:309) at org.eclipse.jetty.websocket.common.extensions.ExtensionStack.incomingFrame(ExtensionStack.java:214) at org.eclipse.jetty.websocket.common.Parser.notifyFrame(Parser.java:220) at org.eclipse.jetty.websocket.common.Parser.parse(Parser.java:258) at org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.readParse(AbstractWebSocketConnection.java:632) at org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.onFillable(AbstractWebSocketConnection.java:480) at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:544) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:635) at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:555) at java.lang.Thread.run(Thread.java:745)