[Bug libgcj/16998] New: WeakHashMap iterator can throw NoSuchElementException unexpectedly

[Bug libgcj/16998] New: WeakHashMap iterator can throw NoSuchElementException unexpectedly

[mckinlay at redhat dot com]

The following test case demonstrates that WeakHashMap's iterator().next() can
throw NoSuchElementException even if hasNext() returned true. This probably
should not be possible - although WeakHashMap is a special case by the spec,
iterator behaviour is not one of those cases. 

It seems reasonable to expect that if hasNext() returns true, next() will not fail.

Possible solution: have hasNext() grab a reference to the element which will be
returned by the subsequent next() call.

import java.util.WeakHashMap;

public class WH {

  public static void main(String[] s) {
    WeakHashMap w = new WeakHashMap();
    for (int i = 0; i < 100000; i++)
      w.put(new WH(), null);

    for (int i = 0; i < 1000; i++)
      System.out.println(w.keySet().toArray().length);
  }
}

-- 
           Summary: WeakHashMap iterator can throw NoSuchElementException
                    unexpectedly
           Product: gcc
           Version: 3.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: libgcj
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: mckinlay at redhat dot com
                CC: gcc-bugs at gcc dot gnu dot org,java-prs at gcc dot gnu
                    dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16998

[Bug libgcj/16998] WeakHashMap iterator can throw NoSuchElementException unexpectedly

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-27 19:46 -------
*** Bug 18187 has been marked as a duplicate of this bug. ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ovidr at users dot
                   |                            |sourceforge dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16998

[Bug libgcj/16998] WeakHashMap iterator can throw NoSuchElementException unexpectedly

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-28 14:25 -------


*** This bug has been marked as a duplicate of 18187 ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16998