小编tra*_*han的帖子

我想在 neo4j 中创建新的数据库“演示”，但我看到一个错误：

我正在搜索但找不到结果，你能帮我吗？谢谢大家！

我运行一个用 Java 编写的 Spark Streaming 程序来从 Kafka 读取数据，但收到此错误，我试图找出可能是因为我使用 scala 或 java 的版本较低。我使用 JDK 版本 15 仍然遇到此错误，有人可以帮我解决此错误吗？谢谢。

这是我运行项目时的终端：

Exception in thread "main" java.lang.NoClassDefFoundError: scala/Product$class
        at org.apache.spark.streaming.kafka010.PreferConsistent$.<init>(LocationStrategy.scala:42)
        at org.apache.spark.streaming.kafka010.PreferConsistent$.<clinit>(LocationStrategy.scala)
        at org.apache.spark.streaming.kafka010.LocationStrategies$.PreferConsistent(LocationStrategy.scala:66)
        at org.apache.spark.streaming.kafka010.LocationStrategies.PreferConsistent(LocationStrategy.scala)
        at demo.KafkaDemo.main(KafkaDemo.java:47)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:564)
        at org.apache.spark.deploy.JavaMainApplication.start(SparkApplication.scala:52)
        at org.apache.spark.deploy.SparkSubmit.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:951)
        at org.apache.spark.deploy.SparkSubmit.doRunMain$1(SparkSubmit.scala:180)
        at org.apache.spark.deploy.SparkSubmit.submit(SparkSubmit.scala:203)
        at org.apache.spark.deploy.SparkSubmit.doSubmit(SparkSubmit.scala:90)
        at org.apache.spark.deploy.SparkSubmit$$anon$2.doSubmit(SparkSubmit.scala:1030)
        at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:1039)
        at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
Caused by: java.lang.ClassNotFoundException: scala.Product$class
        at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:435)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:589)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
        ... 17 more
21/05/31 14:42:51 INFO SparkContext: Invoking stop() from shutdown …