问题
I was trying to import table from MySQL to HDFS using sqoop. The commandline used is,
sqoop import --connect jdbc:mysql://192.168.10.452/qw_key_test --username qw -P --split-by qw_id -m 10 --target-dir /user/perf/qwperf/sqoops --verbose --table qw_perf_store_key
The mappers fails with Unsupported version as show below.
2013-05-22 17:46:24,165 WARN mapreduce.Counters: Group org.apache.hadoop.mapred.Task$Counter is deprecated. Use org.apache.hadoop.mapreduce.TaskCounter instead
2013-05-22 17:46:24,534 WARN org.apache.hadoop.conf.Configuration: session.id is deprecated. Instead, use dfs.metrics.session-id
2013-05-22 17:46:24,535 INFO org.apache.hadoop.metrics.jvm.JvmMetrics: Initializing JVM Metrics with processName=MAP, sessionId=
2013-05-22 17:46:24,835 INFO org.apache.hadoop.util.ProcessTree: setsid exited with exit code 0
2013-05-22 17:46:24,839 INFO org.apache.hadoop.mapred.Task: Using ResourceCalculatorPlugin : org.apache.hadoop.util.LinuxResourceCalculatorPlugin@191410e5
2013-05-22 17:46:25,278 INFO org.apache.hadoop.mapred.TaskLogsTruncater: Initializing logs' truncater with mapRetainSize=-1 and reduceRetainSize=-1
2013-05-22 17:46:25,280 FATAL org.apache.hadoop.mapred.Child: Error running child : java.lang.UnsupportedClassVersionError: qw_perf_store_key : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:247)
at org.apache.hadoop.conf.Configuration.getClassByNameOrNull(Configuration.java:1510)
at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:1475)
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1569)
at org.apache.sqoop.mapreduce.db.DBConfiguration.getInputClass(DBConfiguration.java:276)
at org.apache.sqoop.mapreduce.db.DataDrivenDBInputFormat.createDBRecordReader(DataDrivenDBInputFormat.java:230)
at org.apache.sqoop.mapreduce.db.DBInputFormat.createRecordReader(DBInputFormat.java:236)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:617)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:325)
at org.apache.hadoop.mapred.Child$4.run(Child.java:268)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1332)
at org.apache.hadoop.mapred.Child.main(Child.java:262)
Any Idea? Using CentOS 6.2, CDH4 JDK7_21, sqoop: Sqoop 1.4.1-cdh4.1.3 (git commit id 0ff32b245c1d4c75e9f034414ebd8cfcdd140e7e)
回答1:
The major.minor version 51.0 represents JDK 1.7 which also confirms what you stated. It appears that, the JDK 1.7 is not compatible with Sqoop version 1.4.1-cdh4.1.3. Per this supported JDK requirements for CDH4, JDK 1.7 is supported on CDH 4.2 and later versions.
Install and set the JAVA_HOME to JDK 1.6 using the Oracle JDK Installation and then run the sqoop.
回答2:
I've seen this issue when Sqoop was running on JDK7 whereas the Hadoop cluster was on JDK6. Do make sure that all your java applications are using the same major JDK version and you should be fine.
回答3:
I changes $JAVA_HOME to j2sdk1.6-oracle which Cloudera Manager installed by default. Then I exported the PATH variable to include the bin and it worked.
来源：https://stackoverflow.com/questions/16692205/sqoop-import-failed-unsupportedclassversionerror