final TransactionContext context = client.newTransactionContext();
context.beginTransaction();
final TransactionalMap txMap = context.getMap(mapName);
txMap.put("key2", "value2");
assertTrue(txMap.containsKey("key1"));
assertTrue(txMap.containsKey("key2"));
assertFalse(txMap.containsKey("key3"));
context.commitTransaction();
}