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Mingliang Liu commented on HDFS-7101: ------------------------------------- This is a good catch, and the initial value makes sense to me. If {{readLine()}} throws exception, the following code {{if (lastLine.endsWith(...)}} will not reach as we don't swallow the exception here. I think NPE that is caused by {{lastLine}} only happens if the input stream is empty. Agreed? > Potential null dereference in DFSck#doWork() > -------------------------------------------- > > Key: HDFS-7101 > URL: https://issues.apache.org/jira/browse/HDFS-7101 > Project: Hadoop HDFS > Issue Type: Bug > Affects Versions: 2.5.1 > Reporter: Ted Yu > Assignee: skrho > Priority: Minor > Labels: BB2015-05-TBR > Attachments: HDFS-7101.v1.patch, HDFS-7101_001.patch > > > {code} > String lastLine = null; > int errCode = -1; > try { > while ((line = input.readLine()) != null) { > ... > if (lastLine.endsWith(NamenodeFsck.HEALTHY_STATUS)) { > errCode = 0; > {code} > If readLine() throws exception, lastLine may be null, leading to NPE. -- This message was sent by Atlassian JIRA (v6.3.4#6332)