我正在Coursera中完成“高级机器学习和信号处理”的任务。我遇到此错误“ Py4JavaEror”。这是本课程的第一项作业。据说这是在IBM Watson Studio中完成的，但是在Ibm Watson Studio中这样做太复杂了，而我在google Colab中做了。这是我的代码：
from IPython.display import Markdown, display
def printmd(string):
display(Markdown('# <span style="color:red">'+string+'</span>'))
if ('sc' in locals() or 'sc' in globals()):
printmd('<<<<<!!!!! It seems that you are running in a IBM Watson Studio!>>>>>')
!pip install pyspark==2.4.5
try:
from pyspark import SparkContext, SparkConf
from pyspark.sql import SparkSession
except ImportError as e:
printmd('<<<<<!!!!! Please restart your kernel after installing Apache Spark !!!!!>>>>>')
sc = SparkContext.getOrCreate(SparkConf().setMaster("local[*]"))
spark = SparkSession \
.builder \
.getOrCreate()
df=spark.read.load('a2.parquet')
df.createOrReplaceTempView("df")
spark.sql("SELECT * from df").show()
错误类似：
---------------------------------------------------------------------------
Py4JJavaError Traceback (most recent call last)
/usr/local/lib/python3.6/dist-packages/pyspark/sql/utils.py in deco(*a, **kw)
62 try:
---> 63 return f(*a, **kw)
64 except py4j.protocol.Py4JJavaError as e:
4 frames
Py4JJavaError: An error occurred while calling o530.load.
: java.lang.IllegalArgumentException: Unsupported class file major version 55
at org.apache.xbean.asm6.ClassReader.<init>(ClassReader.java:166)
at org.apache.xbean.asm6.ClassReader.<init>(ClassReader.java:148)
at org.apache.xbean.asm6.ClassReader.<init>(ClassReader.java:136)
at org.apache.xbean.asm6.ClassReader.<init>(ClassReader.java:237)
at org.apache.spark.util.ClosureCleaner$.getClassReader(ClosureCleaner.scala:49)
at org.apache.spark.util.FieldAccessFinder$$anon$3$$anonfun$visitMethodInsn$2.apply(ClosureCleaner.scala:517)
at org.apache.spark.util.FieldAccessFinder$$anon$3$$anonfun$visitMethodInsn$2.apply(ClosureCleaner.scala:500)
at scala.collection.TraversableLike$WithFilter$$anonfun$foreach$1.apply(TraversableLike.scala:733)
at scala.collection.mutable.HashMap$$anon$1$$anonfun$foreach$2.apply(HashMap.scala:134)
at scala.collection.mutable.HashMap$$anon$1$$anonfun$foreach$2.apply(HashMap.scala:134)
at scala.collection.mutable.HashTable$class.foreachEntry(HashTable.scala:236)
at scala.collection.mutable.HashMap.foreachEntry(HashMap.scala:40)
at scala.collection.mutable.HashMap$$anon$1.foreach(HashMap.scala:134)
at scala.collection.TraversableLike$WithFilter.foreach(TraversableLike.scala:732)
at org.apache.spark.util.FieldAccessFinder$$anon$3.visitMethodInsn(ClosureCleaner.scala:500)
at org.apache.xbean.asm6.ClassReader.readCode(ClassReader.java:2175)
at org.apache.xbean.asm6.ClassReader.readMethod(ClassReader.java:1238)
at org.apache.xbean.asm6.ClassReader.accept(ClassReader.java:631)
at org.apache.xbean.asm6.ClassReader.accept(ClassReader.java:355)
at org.apache.spark.util.ClosureCleaner$$anonfun$org$apache$spark$util$ClosureCleaner$$clean$14.apply(ClosureCleaner.scala:307)
at org.apache.spark.util.ClosureCleaner$$anonfun$org$apache$spark$util$ClosureCleaner$$clean$14.apply(ClosureCleaner.scala:306)
at scala.collection.immutable.List.foreach(List.scala:392)
at org.apache.spark.util.ClosureCleaner$.org$apache$spark$util$ClosureCleaner$$clean(ClosureCleaner.scala:306)
at org.apache.spark.util.ClosureCleaner$.clean(ClosureCleaner.scala:162)
at org.apache.spark.SparkContext.clean(SparkContext.scala:2326)
at org.apache.spark.SparkContext.runJob(SparkContext.scala:2100)
at org.apache.spark.SparkContext.runJob(SparkContext.scala:2126)
at org.apache.spark.rdd.RDD$$anonfun$collect$1.apply(RDD.scala:990)
at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:151)
at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:112)
at org.apache.spark.rdd.RDD.withScope(RDD.scala:385)
at org.apache.spark.rdd.RDD.collect(RDD.scala:989)
at org.apache.spark.sql.execution.datasources.parquet.ParquetFileFormat$.mergeSchemasInParallel(ParquetFileFormat.scala:633)
at org.apache.spark.sql.execution.datasources.parquet.ParquetFileFormat.inferSchema(ParquetFileFormat.scala:241)
at org.apache.spark.sql.execution.datasources.DataSource$$anonfun$6.apply(DataSource.scala:180)
at org.apache.spark.sql.execution.datasources.DataSource$$anonfun$6.apply(DataSource.scala:180)
at scala.Option.orElse(Option.scala:289)
at org.apache.spark.sql.execution.datasources.DataSource.getOrInferFileFormatSchema(DataSource.scala:179)
at org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:373)
at org.apache.spark.sql.DataFrameReader.loadV1Source(DataFrameReader.scala:223)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:211)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:178)
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 py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
at py4j.Gateway.invoke(Gateway.java:282)
at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
at py4j.commands.CallCommand.execute(CallCommand.java:79)
at py4j.GatewayConnection.run(GatewayConnection.java:238)
at java.base/java.lang.Thread.run(Thread.java:834)
During handling of the above exception, another exception occurred:
IllegalArgumentException Traceback (most recent call last)
/usr/local/lib/python3.6/dist-packages/pyspark/sql/utils.py in deco(*a, **kw)
77 raise QueryExecutionException(s.split(': ', 1)[1], stackTrace)
78 if s.startswith('java.lang.IllegalArgumentException: '):
---> 79 raise IllegalArgumentException(s.split(': ', 1)[1], stackTrace)
80 raise
81 return deco
IllegalArgumentException: 'Unsupported class file major version 55'
这里，
这是因为您的Java的运行时版本为11
Spark可在Java 8，Python 2.7 + / 3.4 +和R 3.1+上运行。对于Scala API，Spark 2.4.4使用Scala 2.12。您将需要使用兼容的Scala版本（2.12.x）
尝试安装版本8的其他Java，并将JAVA_HOME指向新安装的Java。