code: protected boolean evaluate4Instance()
          throws EFapsException
      {
          boolean ret = true;
          if (!isSearchMode()) {
              final List<Return> returns = this.getCommand().executeEvents(EventType.UI_TABLE_EVALUATE,
                              ParameterValues.INSTANCE, getInstance(),
                              ParameterValues.PARAMETERS, Context.getThreadContext().getParameters(),
                              ParameterValues.CLASS, this);
              for (final Return retu : returns) {
                  if (retu.contains(ReturnValues.INSTANCE)) {
                      final Object object = retu.get(ReturnValues.INSTANCE);
                      if (object != null && object instanceof Instance && ((Instance) object).isValid()) {
                          setInstanceKey(((Instance) object).getOid());
                      } else {
                          UIForm.LOG.error("The esjp called by Command '{}' must return a valid instance",
                                          this.getCommand().getName());
                      }
                  } else {
                      ret = false;
                  }
              }
          }
          return ret;
      }
docs: This is a possibility to replace the current Instance for the form with
  another one using an table evaluate esjp.
  
  @return true, if successful
  @throws EFapsException on error