[HADOOP-387] LocalJobRunner assigns duplicate mapid's

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.4.0
• Fix Version/s: 0.5.0

Environment

xp, cygwin, jdk1.4.2_12

• Assignee: Unassigned
• Reporter: Sami Siren
• Created: 25/Jul/06 18:39
• Updated: 08/Jul/09 16:51
• Resolved: 26/Jul/06 07:29

Description

While hunting down nutch issue NUTCH-266 i discovered that id's are generated with following fragment of code:

private String newId()

{ return Integer.toString(Math.abs(new Random().nextInt()),36); }

and the related Javadoc:
"
public Random()

Creates a new random number generator. Its seed is initialized to a value based on the current time:

public Random()

{ this(System.currentTimeMillis()); }

Two Random objects created within the same millisecond will have the same sequence of random numbers.

"

it appears that in this case there are more than one Random pobject generated at the same millisecond and id's are
no longer unique.