hive:appclassloader不能强制转换为urlclassloader，尽管使用的是jdk8

57hvy0tb 于 2021-06-26 发布在 Hive

关注(0)|答案(3)|浏览(379)

安装后 jdk9 我看到了这个问题：

$hive
Java HotSpot(TM) 64-Bit Server VM warning: Ignoring option MaxPermSize; support was removed in 8.0
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/usr/local/Cellar/hive/2.3.1/libexec/lib/log4j-slf4j-impl-2.6.2.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/usr/local/Cellar/hadoop/2.8.1/libexec/share/hadoop/common/lib/slf4j-log4j12-1.7.10.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.apache.logging.slf4j.Log4jLoggerFactory]
Exception in thread "main" java.lang.ClassCastException: java.base/jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to java.base/java.net.URLClassLoader
    at org.apache.hadoop.hive.ql.session.SessionState.<init>(SessionState.java:394)
    at org.apache.hadoop.hive.ql.session.SessionState.<init>(SessionState.java:370)
    at org.apache.hadoop.hive.cli.CliSessionState.<init>(CliSessionState.java:60)
    at org.apache.hadoop.hive.cli.CliDriver.run(CliDriver.java:708)
    at org.apache.hadoop.hive.cli.CliDriver.main(CliDriver.java:686)
    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:564)
    at org.apache.hadoop.util.RunJar.run(RunJar.java:234)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:148)

但我有
更新 $PATH 指向java8

$java -version
java version "1.8.0_144"
Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)

更新 hive 指定java8的可执行文件

vi $(which hive)

# !/bin/bash

JAVA_HOME="$(/usr/libexec/java_home --version 1.8)" HIVE_HOME="/usr/local/Cellar/hive/2.3.1/libexec" exec "/usr/local/Cellar/hive/2.3.1/libexec/bin/hive" "$@"

验证了更新的java版本是否指向jdk8

$/usr/libexec/java_home --version 1.8
/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home

我还应该调查什么？
这是 hive 2.3.1 在 macos ```
$hive --version
Hive 2.3.1
Git git://jcamachorodriguez-rMBP.local/Users/jcamachorodriguez/src/workspaces/hive/HIVE-apache/hive -r 7590572d9265e15286628013268b2ce785c6aa08
Compiled by jcamachorodriguez on Thu Oct 19 18:37:58 PDT 2017
From source with checksum 03c91029a6103bd91f25a6ff8a01fbcd

Java Hive java-9 ClassLoader urlclassloader

来源：https://stackoverflow.com/questions/47897645/hive-appclassloader-cannot-be-cast-to-urlclassloader-although-using-jdk8

3条答案

按热度按时间

dnph8jn41#

我有同样的问题，我只是删除jdk9而不是改变环境，问题就解决了。
看Hive，它用

JAVA_HOME="$(/usr/libexec/java_home --version 1.7+)" 
HIVE_HOME="/usr/local/Cellar/hive/2.3.1/libexec" 
exec "/usr/local/Cellar/hive/2.3.1/libexec/bin/hive" "$@".

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uttx8gqw2#

我在设置配置单元时遇到了相同的错误，最初我认为可能是因为不同的java版本。
但在检查java版本时，它是JDK1.8。
最后，在检查jdk安装目录（/library/java/javavirtualmachine）时，我发现jdk1.8和jdk10都存在
我删除了JDK10，最后它成功了。

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yshpjwxd3#

安装jdk8并在hadoop-env.sh中相应地更改路径，这对我起到了作用。

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