log4j:WARN No appenders could be found for logger (org.apache.hadoop.util.Shell).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Exception in thread "main" java.lang.NullPointerException
at java.lang.ProcessBuilder.start(ProcessBuilder.java:441)
at org.apache.hadoop.util.Shell.runCommand(Shell.java:404)
at org.apache.hadoop.util.Shell.run(Shell.java:379)
at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:589)
at org.apache.hadoop.util.Shell.execCommand(Shell.java:678)
at org.apache.hadoop.util.Shell.execCommand(Shell.java:661)
at org.apache.hadoop.fs.RawLocalFileSystem.setPermission(RawLocalFileSystem.java:639)
at org.apache.hadoop.fs.RawLocalFileSystem.mkdirs(RawLocalFileSystem.java:435)
at org.apache.hadoop.fs.FilterFileSystem.mkdirs(FilterFileSystem.java:277)
at org.apache.hadoop.mapreduce.JobSubmissionFiles.getStagingDir(JobSubmissionFiles.java:125)
at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:344)
at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1268)
at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1265)
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:1491)
at org.apache.hadoop.mapreduce.Job.submit(Job.java:1265)
at org.apache.hadoop.mapred.JobClient$1.run(JobClient.java:562)
at org.apache.hadoop.mapred.JobClient$1.run(JobClient.java:557)
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:1491)
at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:557)
at org.apache.hadoop.mapred.JobClient.submitJob(JobClient.java:548)
at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:833)
at test.WordCount.run(WordCount.java:150)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
at test.WordCount.main(WordCount.java:155)
hadoop运行正常，且wordCount的jar在hadoop上执行是成功的，但是用eclipse上运行就报空指针，运行参数是：
input output
DFS也可以正常的连接上传、下载
报NullPointerException的原因：Hadoop 2.2 Windows下eclipse开发hadoop程序会报错，是因为hadoop2.2没有发布winutils.exe造成的，现编译发布出来； 把此文件放到hadoop/bin下，在环境变量中配置 HADOOP_HOME 即可