[Bug libgcj/11241] New: WeakHashMap throws a "/ zero" ArithmeticException when initialCapacity is explicitly zero

[Bug libgcj/11241] New: WeakHashMap throws a "/ zero" ArithmeticException when initialCapacity is explicitly zero

[mikeb at lshift dot net]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11241

           Summary: WeakHashMap throws a "/ zero" ArithmeticException when
                    initialCapacity is explicitly zero
           Product: gcc
           Version: 3.3
            Status: UNCONFIRMED
          Severity: minor
          Priority: P2
         Component: libgcj
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mikeb@lshift.net
                CC: gcc-bugs@gcc.gnu.org

When a java.util.WeakHashMap is constructed with the initial capacity explicitly
zero, using get() can throw a "/ zero" java.lang.ArithmeticException.  The
problem is in the private hash function, which uses "x % buckets.length".  In
the case of an initial capacity of zero, buckets.length is zero.

I've fixed that immediate problem (test cases and patch coming RSN).  There
appear to be some other problems with WeakHashMap in the same circumstances
though.  I'll work through those now ...

[Bug libgcj/11241] WeakHashMap throws a "/ zero" ArithmeticException when initialCapacity is explicitly zero

[tromey at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11241



------- Additional Comments From tromey at gcc dot gnu dot org  2003-08-01 03:44 -------
Did you ever come up with a test case and patch?

[Bug libgcj/11241] WeakHashMap throws a "/ zero" ArithmeticException when initialCapacity is explicitly zero

[mikeb at lshift dot net]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11241



------- Additional Comments From mikeb at lshift dot net  2003-08-01 13:24 -------
Created an attachment (id=4546)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=4546&action=view)
Simple test case for defect

A fairly amateur test case for the defect described.

[Bug libgcj/11241] WeakHashMap throws a "/ zero" ArithmeticException when initialCapacity is explicitly zero

[pinskia at physics dot uc dot edu]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11241


pinskia at physics dot uc dot edu changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2003-08-01 15:23:11
               date|                            |


------- Additional Comments From pinskia at physics dot uc dot edu  2003-08-01 15:23 -------
I can confirm this in the mainline (20030801).

[Bug libgcj/11241] WeakHashMap throws a "/ zero" ArithmeticException when initialCapacity is explicitly zero

[tromey at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11241


tromey at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |tromey at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED

[Bug libgcj/11241] WeakHashMap throws a "/ zero" ArithmeticException when initialCapacity is explicitly zero

[tromey at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11241


tromey at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


------- Additional Comments From tromey at gcc dot gnu dot org  2003-08-01 21:22 -------
I'm checking in a fix for this.

[Bug libgcj/11241] WeakHashMap throws a "/ zero" ArithmeticException when initialCapacity is explicitly zero

[cvs-commit at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11241



------- Additional Comments From cvs-commit at gcc dot gnu dot org  2003-08-01 21:30 -------
Subject: Bug 11241

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	tromey@gcc.gnu.org	2003-08-01 21:30:14

Modified files:
	libjava        : ChangeLog 
	libjava/java/util: WeakHashMap.java 

Log message:
	Fix for PR libgcj/11241:
	* java/util/WeakHashMap.java (WeakHashMap(int,float)): If
	initialCapacity is 0, set it to 1.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libjava/ChangeLog.diff?cvsroot=gcc&r1=1.2078&r2=1.2079
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libjava/java/util/WeakHashMap.java.diff?cvsroot=gcc&r1=1.6&r2=1.7

[Bug libgcj/11241] WeakHashMap throws a "/ zero" ArithmeticException when initialCapacity is explicitly zero

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11241


pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |scgmille at freenetproject
                   |                            |dot org


------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-17 18:59 -------
*** Bug 12664 has been marked as a duplicate of this bug. ***