[HDFS-1934] Fix NullPointerException when File.listFiles() API returns null

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.23.0
• Fix Version/s: 0.23.0
• Assignee: Bharath Mundlapudi
• Reporter: Bharath Mundlapudi
• Created: 13/May/11 01:19
• Updated: 02/May/13 02:29
• Resolved: 03/Jun/11 10:07

Description

While testing Disk Fail Inplace, We encountered the NPE from this part of the code.

File[] files = dir.listFiles();
for (File f : files) {
...
}

This is kinda of an API issue. When a disk is bad (or name is not a directory), this API (listFiles, list) return null rather than throwing an exception. This 'for loop' throws a NPE exception. And same applies to dir.list() API.

Fix all the places where null condition was not checked.

Issue Links

• is blocked by: HADOOP-7322 Adding a util method in FileUtil for JDK File.listFiles
• is depended upon by: HDFS-2023 Backport of NPE for File.list and File.listFiles
• is related to: HDFS-2137 Datanode Disk Fail Inplace