我们有一个烫伤的工作，我想在aws弹性mapreduce上运行使用发行标签4.2.0。
此作业在ami 2.4.2上成功运行。当我们将它升级到AMI3.7.0时，遇到了一个 java.lang.VerifyError 由不兼容的jar引起的。我们的项目使用commons编解码器库的1.5版本，但是ami附带了早期的不兼容版本。类似地，我们的项目使用Scala2.10，但是版本2.11附带了ami。我们通过添加一个引导脚本来删除所有匹配的文件来解决这个问题 commons-codec-1.[234].jar 或者 scala-library-2.11.*.jar 来自集群。
现在我们要再次升级到4.2.0，再次得到一个verifyerror：

Exception in thread "main" java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at com.twitter.scalding.Job$.apply(Job.scala:47)
at com.twitter.scalding.Tool.getJob(Tool.scala:48)
at com.twitter.scalding.Tool.run(Tool.scala:68)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
at com.snowplowanalytics.snowplow.enrich.hadoop.JobRunner$.main(JobRunner.scala:33)
at com.snowplowanalytics.snowplow.enrich.hadoop.JobRunner.main(JobRunner.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.hadoop.util.RunJar.run(RunJar.java:221)
at org.apache.hadoop.util.RunJar.main(RunJar.java:136)
Caused by: java.lang.VerifyError: Bad type on operand stack
Exception Details:
Location:
com/snowplowanalytics/snowplow/enrich/common/utils/ConversionUtils$.decodeBase64Url(Ljava/lang/String;Ljava/lang/String;)Lscalaz/Validation; @5: invokevirtual
Reason:
Type 'org/apache/commons/codec/binary/Base64' (current frame, stack[0]) is not assignable to 'org/apache/commons/codec/binary/BaseNCodec'
Current Frame:
bci: @5
flags: { }
locals: { 'com/snowplowanalytics/snowplow/enrich/common/utils/ConversionUtils$', 'java/lang/String', 'java/lang/String' }
stack: { 'org/apache/commons/codec/binary/Base64', 'java/lang/String' }
Bytecode:
0000000: 2ab7 008a 2cb6 0090 3a04 bb00 5459 1904
0000010: b200 96b7 0099 3a05 b200 9e19 05b9 00a4
0000020: 0200 b900 aa01 00a7 003e 4eb2 009e bb00
0000030: ac59 b200 4112 aeb6 00b1 b700 b4b2 0041
0000040: 06bd 0004 5903 2b53 5904 2c53 5905 2db6
0000050: 00b9 53b6 00bf b900 c502 00b9 00a4 0200
0000060: b900 c801 00b0
Exception Handler Table:
bci [0, 42] => handler: 42
Stackmap Table:
same_locals_1_stack_item_frame(@42,Object[#182])
same_locals_1_stack_item_frame(@101,Object[#206])

at com.snowplowanalytics.snowplow.enrich.hadoop.EtlJobConfig$.com$snowplowanalytics$snowplow$enrich$hadoop$EtlJobConfig$$base64ToJsonNode(EtlJobConfig.scala:224)
at com.snowplowanalytics.snowplow.enrich.hadoop.EtlJobConfig$.loadConfigAndFilesToCache(EtlJobConfig.scala:126)
at com.snowplowanalytics.snowplow.enrich.hadoop.EtlJob.(EtlJob.scala:139)
... 16 more

探索清除后哪些jar仍保留在群集中：

$ sudo find / -name "*scala-*"
/usr/share/aws/emr/emrfs/cli/lib/scala-library-2.10.5.jar
/usr/share/aws/emr/emrfs/cli/lib/scala-reflect-2.10.4.jar
/usr/share/aws/emr/emrfs/cli/lib/scala-logging-api_2.10-2.1.2.jar
/usr/share/aws/emr/emrfs/cli/lib/nscala-time_2.10-1.2.0.jar
/usr/share/aws/emr/emrfs/cli/lib/scala-logging-slf4j_2.10-2.1.2.jar
$ sudo find / -name "*commons-codec*"
/usr/share/aws/emr/node-provisioner/lib/commons-codec-1.9.jar
/usr/share/aws/emr/emr-metrics/lib/commons-codec-1.6.jar
/usr/share/aws/emr/emr-metrics-client/lib/commons-codec-1.6.jar
/usr/share/aws/emr/emrfs/lib/commons-codec-1.9.jar
/usr/share/aws/emr/hadoop-state-pusher/lib/commons-codec-1.8.jar
/usr/lib/hbase/lib/commons-codec-1.7.jar
/usr/lib/mahout/lib/commons-codec-1.7.jar

AMI4.1.0也出现同样的错误。在3.7.0和4.x.x之间发生了什么变化导致了此问题，我可以做些什么来修复它？