FULL PRODUCT VERSION :
compiled on windows with java version "1.5.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-b64)
Java HotSpot(TM) Client VM (build 1.5.0-b64, mixed mode, sharing)

or java version "1.4.2"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2-b28)
Java HotSpot(TM) Client VM (build 1.4.2-b28, mixed mode)


run on Windows with java version "1.5.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-b64)
Java HotSpot(TM) Client VM (build 1.5.0-b64, mixed mode, sharing)

run on linux with java version "1.5.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-b64)
Java HotSpot(TM) Client VM (build 1.5.0-b64, mixed mode, sharing)



ADDITIONAL OS VERSION INFORMATION :
Windows 2000 SP4 (Microsoft Windows 2000 [Version 5.00.2195]),
Linux (Linux 2.6.4 #1 SMP i686 GNU/Linux)



A DESCRIPTION OF THE PROBLEM :
When creating a new ArrayList passing it a result of entrySet() called on IdentityHashMap of size one, the resulting ArrayList is of size one but contains null instead of a reference to object the original IdentityHashMap contains.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile and run the sample testcase provided.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
ls: [com.parsek.test.BugTest$KeyClass@35ce36=com.parsek.test.BugTest$ValueClass@1a46e30]
ls2: [com.parsek.test.BugTest$KeyClass@35ce36=com.parsek.test.BugTest$ValueClass@1a46e30]
ACTUAL -
ls: [null]
ls2: [com.parsek.test.BugTest$KeyClass@35ce36=com.parsek.test.BugTest$ValueClass@1a46e30]

REPRODUCIBILITY :
This bug can be reproduced always.

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

public class BugTest {

static class KeyClass {
String somefield;
}

static class ValueClass {
String somevalue;
}

public static void main(String [] args) throws Exception {

IdentityHashMap map = new IdentityHashMap();
map.put(new KeyClass(), new ValueClass());

ArrayList ls = new ArrayList(map.entrySet());
System.out.println("ls: " + ls);

LinkedList ls2 = new LinkedList(map.entrySet());
System.out.println("ls2: " + ls2);

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

CUSTOMER SUBMITTED WORKAROUND :
Use LinkedList or HashSet instead of ArrayList
###@###.### 2005-2-24 02:21:22 GMT