docs: public final void persistentRepresentationIsUnstable() throws SevereMessageStoreException
      {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.entry(this, tc, "persistentRepresentationIsUnstable");
  
          boolean notifyRequired = false;
          synchronized (this)
          {
              // we are going to need the item in memory, so we make sure that
              // we pin it with a hard reference
              if (_strongReferenceToItem == NULL_STRONG_REF && null != _softReferenceToItem)
              {
                  // Someone else may still have a reference to the item,
                  // so we can save some trouble by recovering the item
                  // from the weak reference. If the weak reference has been
                  // cleared then the item will still be null, and the calling
                  // code will just need to cope with it.
                  _strongReferenceToItem = (AbstractItem) _softReferenceToItem.get();
  
                  // Defect 601995
                  // Set the reference to the named class if still null
                  // after the call to the soft reference.
                  if (_strongReferenceToItem == null)
                  {
                      _strongReferenceToItem = NULL_STRONG_REF;
                  }
              }
  
              if (_persistentRepresentationIsStable)
              {
                  // if we have become unstable, and we were releasable
                  // then we need to notify cache
                  notifyRequired = _itemIsDiscardableIfPersistentRepresentationStable;
                  _persistentRepresentationIsStable = false;
              }
  
              if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
                  SibTr.debug(this, tc, "stable=false available=" + _itemIsDiscardableIfPersistentRepresentationStable);
          }
  
          if (notifyRequired)
          {
              _declareNotReleasable();
          }
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.exit(this, tc, "persistentRepresentationIsUnstable");
      }