Randomly select columns in cassandra

I use this code to extract user_id and user_code

Keyspace keyspace = HFactory.createKeyspace("test", cluster);
CqlQuery<String,String,ByteBuffer> cqlQuery = new CqlQuery<String,String,ByteBuffer>(keyspace, stringSerializer, stringSerializer, new ByteBufferSerializer());
cqlQuery.setQuery("select user_id,user_code from User");
QueryResult<CqlRows<String,String,ByteBuffer>> result = cqlQuery.execute();
Iterator iterator = result.get().iterator();
while(iterator.hasNext()) {
    Row<String, String, ByteBuffer> row =  (Row<String, String, ByteBuffer>) iterator.next();
    System.out.println("\nInserted data is as follows:\n" + row.getColumnSlice().getColumns().get(0).getValue().getInt());
    System.out.println("\nInserted data is as follows:\n" + Charset.forName("UTF-8").decode(row.getColumnSlice().getColumns().get(1).getValueBytes()));
}

Now the problem is that I convert the fields according to their specific type

What if the request goes randomly? How to deal with this scenario?