code: public void clear(Transaction transaction)
                      throws ObjectManagerException
      {
          if (Tracing.isAnyTracingEnabled() && trace.isEntryEnabled())
              trace.entry(this, cclass,
                          "clear",
                          new Object[] { transaction });
  
          try {
              for (Iterator iterator = iterator();;) {
                  iterator.next(transaction);
                  iterator.remove(transaction);
              } // for...  
          } catch (java.util.NoSuchElementException exception) {
              // No FFDC code needed.
              // We have run off the end of the other collection.
          } // try. 
  
          if (Tracing.isAnyTracingEnabled() && trace.isEntryEnabled())
              trace.exit(this, cclass,
                         "clear");
      }
docs: retainAll().