Make Cassandra compile under JDK 7

    [javac] /usr/src/cassandra/drivers/java/src/org/apache/cassandra/cql/jdbc/CResultSet.java:39: error: CResultSet is not abstract and does not override abstract method <T>getObject(String,Class<T>) in ResultSet
    [javac] class CResultSet extends AbstractResultSet implements CassandraResultSet
    [javac] ^
    [javac]   where T is a type-variable:
    [javac]     T extends Object declared in method <T>getObject(String,Class<T>)
    [javac] /usr/src/cassandra/drivers/java/src/org/apache/cassandra/cql/jdbc/CassandraConnection.java:81: error: CassandraConnection is not abstract and does not override abstract method getNetworkTimeout() in Connection
    [javac] class CassandraConnection extends AbstractCassandraConnection implements Connection
    [javac] ^
    [javac] /usr/src/cassandra/drivers/java/src/org/apache/cassandra/cql/jdbc/CassandraDataSource.java:24: error: CassandraDataSource is not abstract and does not override abstract method getParentLogger() in CommonDataSource
    [javac] public class CassandraDataSource implements DataSource
    [javac]        ^
    [javac] /usr/src/cassandra/drivers/java/src/org/apache/cassandra/cql/jdbc/CassandraDatabaseMetaData.java:32: error: CassandraDatabaseMetaData is not abstract and does not override abstract method generatedKeyAlwaysReturned() in DatabaseMetaData
    [javac] class CassandraDatabaseMetaData implements DatabaseMetaData
    [javac] ^
    [javac] /usr/src/cassandra/drivers/java/src/org/apache/cassandra/cql/jdbc/CassandraDriver.java:40: error: CassandraDriver is not abstract and does not override abstract method getParentLogger() in Driver
    [javac] public class CassandraDriver implements Driver
    [javac]        ^
    [javac] /usr/src/cassandra/drivers/java/src/org/apache/cassandra/cql/jdbc/CassandraStatement.java:50: error: CassandraStatement is not abstract and does not override abstract method isCloseOnCompletion() in Statement
    [javac] class CassandraStatement extends AbstractStatement implements Statement
    [javac] ^
    [javac] /usr/src/cassandra/drivers/java/src/org/apache/cassandra/cql/jdbc/CassandraPreparedStatement.java:61: error: CassandraPreparedStatement is not abstract and does not override abstract method isCloseOnCompletion() in Statement
    [javac] class CassandraPreparedStatement extends CassandraStatement implements PreparedStatement
    [javac] ^
    [javac] Note: /usr/src/cassandra/drivers/java/src/org/apache/cassandra/cql/jdbc/CassandraPreparedStatement.java uses or overrides a deprecated API.