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From "Allen Wittenauer (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-2364) metaSave API is using Printwriter, It will eat all the IOExceptions.
Date Thu, 17 Jul 2014 21:26:04 GMT

    [ https://issues.apache.org/jira/browse/HDFS-2364?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14065576#comment-14065576

Allen Wittenauer commented on HDFS-2364:


> metaSave API is using Printwriter, It will eat all the IOExceptions.
> --------------------------------------------------------------------
>                 Key: HDFS-2364
>                 URL: https://issues.apache.org/jira/browse/HDFS-2364
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>          Components: namenode
>            Reporter: Uma Maheswara Rao G
>            Assignee: Uma Maheswara Rao G
> It is important to note that
> PrintStream and PrintWriter do not throw IOExceptions! IOException is a
> non-Runtime exception, which means that your code must catch them or declare it
> can throw them.
> The creators of Java realized that System.out and System.err would be very
> heavily used, and did not want to force inclusion of exception handling every time
> you wanted to write System.out.println(4).
> Therefore, PrintStream and PrintWriter catch their own exceptions and set an
> error flag. If you are using one of these classes for real output in your program
> (not merely using System.out.println()) you should call checkError() to see
> if an error has occurred.
> Because of this behavior, PrintStream and PrintWriter are not well suited for
> use other than System.out and System.err!
> Ref: http://www.cs.usfca.edu/~parrt/doc/java/JavaIO-notes.pdf

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