1Z0-819 JDBC 3

Question 1

Which `ResultSet` getter retrieves a column value by its 1-based column index as a `String`?

Accepted Answer

getString(1)

Answer

JDBC ResultSet column indices are 1-based, so `getString(1)` retrieves the first column as a String.

Question 2

What is the correct JDBC URL format for connecting to a local MySQL database named `testdb` on the default port?

Accepted Answer

jdbc:mysql://localhost:3306/testdb

Answer

A standard JDBC URL follows the pattern `jdbc:://:/`, so `jdbc:mysql://localhost:3306/testdb` is correct.

Question 3

Which method closes a `ResultSet`, `Statement`, and `Connection` together when used in a try-with-resources block?

Accepted Answer

Each implements AutoCloseable so all are closed automatically by try-with-resources

Answer

`Connection`, `Statement`, and `ResultSet` all implement `AutoCloseable`, so they are automatically closed at the end of a try-with-resources block.

Question 4

What does `Statement.executeBatch()` return?

Accepted Answer

An int[] where each element is the update count for the corresponding command

Answer

`executeBatch()` returns an `int[]` array where each element represents the update count for the corresponding SQL command added via `addBatch()`.

Question 5

Which `ResultSet` constant specifies that the cursor can scroll both forward and backward and is insensitive to database changes?

Accepted Answer

ResultSet.TYPE_SCROLL_INSENSITIVE

Answer

`ResultSet.TYPE_SCROLL_INSENSITIVE` allows bidirectional scrolling but does not reflect changes made to the database after the ResultSet was opened.

(1Z0-819) Oracle Java SE 11 Developer Practice Test