@Override
      public Object call() throws Exception {
        Region custRegion = getCache().getRegion(CUSTOMER);
        Context ctx = getCache().getJNDIContext();
        UserTransaction tx = (UserTransaction) ctx.lookup("java:/UserTransaction");
        if (isCommit) {
          tx.commit();
          assertThat(expectedCustomer).isEqualTo(custRegion.get(expectedCustId));
        } else {
          tx.rollback();
          assertThat(custRegion.get(expectedCustId)).isNull();
        }
        return null;
      }
@return first key found on the given member
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/RemoteTransactionDUnitTest.java