我已经安装了apachehadoop2.7.1并集成了apachesqoop1.4.6。当我尝试使用sqoop命令从mysql数据库导入到配置单元时：

sqoop import \
--connect "jdbc:mysql://localhost:3306/assignment5" \
--username root \
--password cg \
--table emp_detail \
--fields-terminated-by ',' \
--lines-terminated-by '\n' \
--hive-home /user/hive/warehouse/assignment5.db \
--hive-import  \
--hive-table emp_detail

我得到的问题是：

Exception in thread "main" java.lang.IncompatibleClassChangeError: Found interface org.apache.hadoop.mapreduce.JobContext, but class was expected
            at org.apache.sqoop.config.ConfigurationHelper.getJobNumMaps(ConfigurationHelper.java:65)
            at com.cloudera.sqoop.config.ConfigurationHelper.getJobNumMaps(ConfigurationHelper.java:36)
            at org.apache.sqoop.mapreduce.db.DataDrivenDBInputFormat.getSplits(DataDrivenDBInputFormat.java:125)
            at org.apache.hadoop.mapreduce.JobSubmitter.writeNewSplits(JobSubmitter.java:301)
            at org.apache.hadoop.mapreduce.JobSubmitter.writeSplits(JobSubmitter.java:318)
            at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:196)
            at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1290)
            at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1287)
            at java.security.AccessController.doPrivileged(Native Method)
            at javax.security.auth.Subject.doAs(Subject.java:422)
            at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1657)
            at org.apache.hadoop.mapreduce.Job.submit(Job.java:1287)
            at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:1308)
            at org.apache.sqoop.mapreduce.ImportJobBase.doSubmitJob(ImportJobBase.java:196)
            at org.apache.sqoop.mapreduce.ImportJobBase.runJob(ImportJobBase.java:169)
            at org.apache.sqoop.mapreduce.ImportJobBase.runImport(ImportJobBase.java:266)
            at org.apache.sqoop.manager.SqlManager.importTable(SqlManager.java:673)
            at org.apache.sqoop.tool.ImportTool.importTable(ImportTool.java:497)
            at org.apache.sqoop.tool.ImportTool.run(ImportTool.java:605)
            at org.apache.sqoop.Sqoop.run(Sqoop.java:143)
            at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
            at org.apache.sqoop.Sqoop.runSqoop(Sqoop.java:179)
            at org.apache.sqoop.Sqoop.runTool(Sqoop.java:218)
            at org.apache.sqoop.Sqoop.runTool(Sqoop.java:227)
            at org.apache.sqoop.Sqoop.main(Sqoop.java:236)

谁能告诉我这个问题是什么意思吗？