How to query count from a cassandra table using the DataStax Java Driver

Querying the count of rows from a Cassandra table in a Java application could be a bit tricky, because you can’t use the com.datastax.driver.mapping.Result<T> return type with the returned Long value returned by the count.

If you are trying to do that you could get an exception containing something like this:

@Table annotation was not found on class java.lang.Long

Yes the Result<T> type can only be used if you have a @Table annotated class. But this solution is not for returning counts.

To return the count, you have to use com.datastax.driver.core.ResultSet as your return type. You could have a query like this in your @Accessor interface.

public interface MyAccessor {

    @Query("SELECT COUNT(*) FROM tableName")
    ResultSet countAll();


Then, in your DAO, where you use this accessor, you can do the following to get the long value:

long count = this.myAccessor.countAll().one().getLong(0);


Codec not found for requested operation: [date <-> java.util.Date] exception in Cassandra

I was trying to create an Accessor interface in a Java application communicating with cassandra. The interface looked something like this:

import java.util.Date;

import com.datastax.driver.mapping.Result;
import com.datastax.driver.mapping.annotations.Accessor;
import com.datastax.driver.mapping.annotations.Query;
import com.custom.package.Order;

public interface OrderAccessor {

    @Query("SELECT * FROM orders WHERE checkout_date = ?")
    Result<Order> findAllOrdersByCheckoutDate(Date checkoutDate);


When I was trying to run the query, I got the following exception:

Codec not found for requested operation: [date <-> java.util.Date]

It turned out that for the Cassandra date type, the correct Java type to use is com.datastax.driver.core.LocalDate

Changing my java.util.Date to this resolved the issue.