[HADOOP-1178] NullPointer Exception in org.apache.hadoop.dfs.NameNode.isDir on namenode restart

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.13.0
• Fix Version/s: 0.13.0
• Assignee: Dhruba Borthakur
• Reporter: Dhruba Borthakur
• Created: 28/Mar/07 21:39
• Updated: 08/Jul/09 16:42
• Resolved: 30/Mar/07 17:49

Description

On a namenode restart, I sometimes get the following exception. The problem is that the RPC server is initialized before the namenode data structures are initialized. This means that an RPC starts getting processed by the namenode before its data structures are consistent. The fix is to first initialize the namesystem and then start the RPC server.

NFO org.apache.hadoop.ipc.Server: IPC Server handler 1 on 50000 call error: java.io.IOException: java.lang.NullPointerException
java.io.IOException: java.lang.NullPointerException
at org.apache.hadoop.dfs.NameNode.isDir(NameNode.java:438)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:339)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:564)