[Bug classpath/24858] New: clone does not work with ThreadLocal

[subanark at gmail dot com]

Although ThreadLocal does not allow cloning by itsself, subclasses can enable
this. The implementation of ThreadLocal uses a private key to retrieve data
from the WeakHashMap. clone() copies this key and causes cloned ThreadLocals to
mirror each other rather than being a new unique ThreadLocal. Note that Sun's
implementation is also broken, just in a different way, in that the new cloned
threadlocal does not have its value set.

Sample:
public class Test extends ThreadLocal implements Cloneable
{
   public static void main(String[] args) throws Exception
   {
      Test t = new Test();
      t.set("Test");
      Test t2 = (Test) t.clone();
      System.out.println(t2.get());
      t.set("Test2");
      System.out.println(t2.get());
   }
}

classpath's output:
Test
Test2

Sun's output:
null
null

Expected output:
Test
Test


-- 
           Summary: clone does not work with ThreadLocal
           Product: classpath
           Version: 0.18
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: classpath
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: subanark at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24858