Livy start new session - scala

Question

I have a problem when I want to create a new session by livy the session dead after their creation, I have installed Livy , spark 3.0.0 , scala 1.12.10 and python 3.7.I followed these steps:
step 01 : start Livy server
./livy-server start
step 02 : start spark shell
spark-shell
step 03 : executing this code using python 3 :
import json, pprint, requests, textwrap
host = 'http://localhost:8998'
data = {'kind': 'spark'}
headers = {'Content-Type': 'application/json'}
r = requests.post(host + '/sessions', data=json.dumps(data), headers=headers)
r.json()
session_url = host + r.headers['location']
r = requests.get(session_url, headers=headers)
r.json()
statements_url = session_url + '/statements'
data = {'code': '1 + 1'}
r = requests.post(statements_url, data=json.dumps(data), headers=headers)
r.json()
statement_url = host + r.headers['location']
r = requests.get(statement_url, headers=headers)
pprint.pprint(r.json())
data = {
'code': textwrap.dedent("""
val NUM_SAMPLES = 100000;
val count = sc.parallelize(1 to NUM_SAMPLES).map { i =>
val x = Math.random();
val y = Math.random();
if (x*x + y*y < 1) 1 else 0
}.reduce(_ + _);
println(\"Pi is roughly \" + 4.0 * count / NUM_SAMPLES)
""")
}
r = requests.post(statements_url, data=json.dumps(data), headers=headers)
pprint.pprint(r.json())
statement_url = host + r.headers['location']
r = requests.get(statement_url, headers=headers)
pprint.pprint(r.json())
this is the log of my session :
stderr:
20/02/17 14:20:06 WARN Utils: Your hostname, zekri-VirtualBox resolves to a loopback address: 127.0.1.1; using 10.0.2.15 instead (on interface enp0s3)
20/02/17 14:20:06 WARN Utils: Set SPARK_LOCAL_IP if you need to bind to another address
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.apache.spark.unsafe.Platform (file:/usr/local/spark-3.0.0-preview2-bin-hadoop2.7/jars/spark-unsafe_2.12-3.0.0-preview2.jar) to constructor java.nio.DirectByteBuffer(long,int)
WARNING: Please consider reporting this to the maintainers of org.apache.spark.unsafe.Platform
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
20/02/17 14:20:07 WARN NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
log4j:WARN No appenders could be found for logger (io.netty.util.internal.logging.InternalLoggerFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Exception in thread "main" java.lang.NoClassDefFoundError: scala/Function0$class
at org.apache.livy.shaded.json4s.ThreadLocal.<init>(Formats.scala:311)
at org.apache.livy.shaded.json4s.DefaultFormats$class.$init$(Formats.scala:318)
at org.apache.livy.shaded.json4s.DefaultFormats$.<init>(Formats.scala:296)
at org.apache.livy.shaded.json4s.DefaultFormats$.<clinit>(Formats.scala)
at org.apache.livy.repl.Session.<init>(Session.scala:66)
at org.apache.livy.repl.ReplDriver.initializeSparkEntries(ReplDriver.scala:41)
at org.apache.livy.rsc.driver.RSCDriver.run(RSCDriver.java:337)
at org.apache.livy.rsc.driver.RSCDriverBootstrapper.main(RSCDriverBootstrapper.java:93)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.apache.spark.deploy.JavaMainApplication.start(SparkApplication.scala:52)
at org.apache.spark.deploy.SparkSubmit.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:928)
at org.apache.spark.deploy.SparkSubmit.doRunMain$1(SparkSubmit.scala:180)
at org.apache.spark.deploy.SparkSubmit.submit(SparkSubmit.scala:203)
at org.apache.spark.deploy.SparkSubmit.doSubmit(SparkSubmit.scala:90)
at org.apache.spark.deploy.SparkSubmit$$anon$2.doSubmit(SparkSubmit.scala:1007)
at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:1016)
at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
Caused by: java.lang.ClassNotFoundException: scala.Function0$class
at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:471)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
... 20 more