docs: public synchronized boolean containsKey(Object key
                                              , Transaction transaction
                      )
                                      throws ObjectManagerException
      {
          if (Tracing.isAnyTracingEnabled() && trace.isEntryEnabled())
              trace.entry(this, cclass
                          , "get"
                          , new Object[] { key, transaction });
  
          boolean returnValue = false;
          if (getEntry(key, transaction) != null)
              returnValue = true;
  
          if (Tracing.isAnyTracingEnabled() && trace.isEntryEnabled())
              trace.exit(this, cclass
                         , "containsKey"
                         , "returns " + returnValue + "(boolean)"
                              );
          return returnValue;
      }