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  1. JDK
  2. JDK-6939260

(fs) BasicFileAttributes.lastModifiedTime() should return last modified time with higher precision

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Details

    • Enhancement
    • Resolution: Fixed
    • P4
    • 8
    • 6u15
    • core-libs
    • b75
    • x86
    • linux_ubuntu
    • Verified

    Description

      FULL PRODUCT VERSION :
      java version "1.6.0_15"
      Java(TM) SE Runtime Environment (build 1.6.0_15-b03)
      Java HotSpot(TM) 64-Bit Server VM (build 14.1-b02, mixed mode)

      ADDITIONAL OS VERSION INFORMATION :
      Linux universe 2.6.31-20-generic #58-Ubuntu SMP Fri Mar 12 04:38:19 UTC 2010 x86_64 GNU/Linux


      EXTRA RELEVANT SYSTEM CONFIGURATION :
      ext4 hard disk partition


      A DESCRIPTION OF THE PROBLEM :
      incorrect precision of lastModified() of java.io.File on Ubuntu x64 Linux

      According to https://ext4.wiki.kernel.org/index.php/Ext4_Howto#Inode-related_features

      ext4 support time precision up to nanosecond

      According to http://java.sun.com/javase/6/docs/api/java/io/File.html#lastModified%28%29

      the lastModified() function support resolution up to microsecond.

      In fact, the function also return '000' at the end of number, which is inaccurate

      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      list a directory by the following shell command (will show the full timestamp)

      ls -la --full-time /

      write a simple java program to display the lastModified time of any file

      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      lastModified time up to microseconds should be shown
      ACTUAL -
      The end of the number is always 000, which is inaccurate

      REPRODUCIBILITY :
      This bug can be reproduced always.

      ---------- BEGIN SOURCE ----------
      import java.io.*;

      public class test {

          public static void main(String[] args) throws Throwable {
              String path="/etc/fstab";
              System.out.println("File: "+path+" , last modified: "+Long.toString(new java.io.File(path).lastModified()));
          }

      }
      ---------- END SOURCE ----------

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            alanb Alan Bateman
            ndcosta Nelson Dcosta (Inactive)
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              Created:
              Updated:
              Resolved:
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